Wrote this up for some guildies and happened to have it in mind when I saw some folks posting about it. Hopefully some of you find it useful. Also, I just wrote this off the cuff so some of my math/numbers might be off, but it should all be pretty close.
Generally you should prioritize something like this:
Stam (Note: You really do want about 20k hp raid buffed though)
With all other stats being worthless. Spellpower is probably your highest priority because it helps make those hots so much more effective.
Spirit vs Int is more interesting now. 3.0 I would have told you go to for Spirit always, but after the nerf and the focus on replenishment, I see them as more or less equal. Realistically your gear is going to have a mix anyway and 99% of your enchants are going to be Spellpower.
Haste vs Crit is more difficult to quantify. Living Seed has made crit a very interesting stat for us. It helps solve the problem of crit heals generally being overheal by putting up a damage shield = to 30% of your crit heal. This will often be 3k-4k worth of healing on a reasonably well set up Nourish (Triple Lifebloom blooms have hit well into 20k heal on a crit but it unfortunately doesn't play with Living Seed.) Haste is tempting because of the lowered global cooldown and speeding up those Nourish Spams. Right now I'm leaning towards Crit when given the choice between two equal sets of gear (common in Heroic/Naxx level items). Uld stuff seems to lean towards Crit. Haste cap w/ GotEM is 359 for a reference point. (Celestial Focus 3% spell haste talent = 253). MP5 is useful, but really doesn't benefit from our talents. Don't run away screaming from it, but it's sorta "Meh".
There are no specific "minimums" to shoot for. You either have the mana to finish boss fights or you don't. You either are surviving the tantrums or you are not. The only two numbers I tend to look at as being targets are:
Hitpoints - 20k, with more being better (Buffed)
Mana Regen - 400-500 mp5, with more sometimes being better, but usually is overkill (Buffed)
Everything else is preference, really.
Red = Runed Scarlet Ruby (+19 Spell Power)
Yellow = Luminous Monarch Topaz (+8 Int +9 Spell Power)
Blue = Purified Twilight Opal (+8 Spirit +9 Spellpower)
For the Meta-Gem I've really, really gotten to like the Insightful Earthsiege Diamond. It's 600 mana a proc and has a 5% chance to pop per cast, which means it's proccing all the time.Ozmethod puts the numbers at "30 Casts per minute, or one every 2 seconds, IED gives 75 mp5. At 40 cpm, or every 1.5 seconds, it gives 100 mp5. At 60 CPM, which would be a haste-GCD capped druid spamming nonstop, 150 mp5." I've worked on the assumption it provides about 80 mp5. I probably over-value mana regen, but it brings a smile to my face when the other healers are winded and I'm able to keep on chugging.
Leather vs Cloth
I my opinion, try to stay with leather if at all possible. Early in your gearing cloth is perfectly acceptable, but Tree of Life now grants an armor bonus similar to bear form so it's relevant. You're looking at about 45% damage reduction on physical damage which places us right near Shaman for squishiness - i.e. not bad. And yes, even good tanks sometimes can't catch an add in time. If you don't think 1% damage reduction makes a difference, think of how many times you've seen somebody survive with 12 - 200 hp.
Additionally, you can buy a very good healing set off of the AH or craft it extremely cheaply. Druids are lucky this way. Between cloth and leather and the various jewelries, our hardest slot to fill is the trinket, but there are many +SP trinkets and some +MP5 ones that you can get from quests that fit the bill nicely.
For emphasis, I do not believe that you should roll on cloth against a priest/mage/warlock. I would also not let good cloth get sharded if it was an upgrade. A fresh 80 will almost certainly be wearing a few pieces of cloth. An experienced 80 may have a piece here and there. If you're trying to min/max you may find you have to rely on cloth for Best in Slot gear.
Lots of argument on the glyphs in the druid community. Part of it will depend on your play style and part of it your gear level. Generally the used glyphs are:
Lifebloom (Drifting towards obsolete, I'd need to see math that makes it worthwhile)
Healing Touch (Obsolete)
In my opinion the only one set in stone is Swiftmend (And not everybody feels this way). It's simply too mana efficient and convenient to not get. One of the most common moves you'll pull is to throw a Rejuv on a butchered dps followed by an immediate SM. The SM will knock them up out of the danger zone and the Rejuv will continue ticking to top them off.
I'm also using the Wild Growth and Nourish Glyphs. WG accounts for a tremendous amount of healing. It's also instant cast and will generally heal affected members for about 2k before your other spells even have a chance to land (it ticks every second). The glyph is more useful as a 25 man tool than a 10 though, as even in 25 it can be tough to hit the full 6 targets.
Nourish vs Healing Touch was a 3.0 debate. I liked the 3.0 HT glyph myself. With the recent changes to Nourish it's very difficult to justify going back to HT in 3.1. Nourish is simply more efficient.
I would recommend that a Druid with fresher gear look at the Innervate glyph. A healer without mana is worthless, no matter what else can be said. Upcoming changes are going to make Innervate a set amount of mana regenned (15k, give or take) so it will be a much more flexible tool for casting on other people (Prior to this it was either cast on a druid or a priest, and that was it). I'm considering swapping out to this glyph myself in place of Nourish or Wild Growth, although the jury is still out yet.
The Rejuvination glyph looks good on paper and is actually pretty good for 5 mans. It generally sucks for 10 and 25's though, as anybody who has health low enough to benefit from the proc is almost certainly being targetted by other raid healers.
Degrador put together a very nice write-up for druid specs. I've copied it here to keep things condensed into one package. I've also made some very minor editting adjustments to integrate it more naturally into this post and fix some very, very rare typos.
"IMO the base line Resto PvE spec looks like this:
From here you have 11 points to spend, with your options as follows:
Nature's Grace: Nature's Grace is primarily a boomkin talent, however it can also be quite useful for tank healing resto druids. The best healing output for tank healing as a resto druid is to have 3xLB plus all other HoTs rolling on the tank whilst spamming Nourish in between. With Nature's Bounty, Nourish has a ~50% chance to crit when raid buffed, and Nature's Grace puts the cast time down to ~1s, so you should have Nature's Grace up almost 100% of the time. That's a huge increase for 3 measily talent points. If you're not tank healing though, the benefit is nowhere near as good. It still can be useful if you're spamming Regrowths on the raid, but otherwise it's pretty useless for HoTs.
1xBrambles + 3xCelestial Focus: This used to be a popular choice pre-3.1 due to the lack of better options in the resto tree, but since then this option just isn't as attractive. The 3% haste from Celestial Focus can help you reach the GCD cap for HoTs a lot easier (cap is 253 with 3xCelestial Focus, and 359 without it), but you basically have to give up either Tranquil Spirit or Revitalise to do it, and IMO both of those are much more useful.
Naturalist: Naturalist is only worth considering if you are going for the HT spec, but with the 3.1 changes to Nourish that spec just isn't as viable anymore. As such there really isn't much point in spending points here.
Tranquil Spirit: As before, the HT spec isn't viable anymore, so the only benefit here is to Nourish. Having said that, it's quite a large benefit to your mana efficiency, and given that it's a reduction in cost rather than actual regen it means it's useful in fights where regen is gimped (General Vezax). Whether or not you need to take this strongly depends on your gear and your healing style. If you're well geared or you don't use Nourish much, then there really isn't much point getting this talent. Otherwise, it can certainly be worth it. The only way to know for sure is to try with & without it to see how you cope mana wise.
Improved Tranquility: Tranquility is a very powerful healing spell. It provides ~2k HPS to every person in your party for a channeled time of 10s. Unfortunately the long CD basically only makes it useful for 1 cast per boss fight, however this talent reduces it to a 4 min CD easily giving you two, possibly three casts in a fight. I can see this being quite useful in a 10 man raid as that party wide heal is for half the raid, however in 25 mans you're much less likely to get the full benefit of this - it's unlikely everyone in your party will need the healing, especially given there are a lot of other healers who will likely heal your party, so IMO it's not really worth 2 talent points for what is still ultimately a panic button.
Natural Perfection: Primarily a PvP talent, Natural Perferction is still useful in PvE for the 3% crit chance. Again, the usefulness of this talent depends on your healing style (tank vs raid healing), but personally I think that even for tank healing there are more useful talents to go for than the 3% crit. Note that it does have some synergy with Living Seed and Nature's Grace, but even still crit is not the most useful stat to resto druids.
Living Seed: Pre 3.1 this talent was a marginal one and often debated amongst resto druids as to the effectiveness of it. Since then, however, it's mostly accepted as being a core resto druid talent. Pre 3.1 it only used to apply to the effective healing done (overheals were ignored), however it now applies to the total healing, and with the buffs to Nourish (particularly Nature's Bounty) you'll likely find Living Seed contributing to 5+% of your healing done, which is quite a lot for 3 talent points. One key thing to remember about the seed is that it still acts as a heal after the damage, rather than a shield to prevent it. That means that if you've got a seed for 3k on someone with 2k health, and they take 3k damage, they will still die before the seed procs to heal them.
Revitalize: The usefulness of this talent is still debatable. Basically there is a 15% chance per Rejuv tick, or 3% chance per WG tick (per person, regardless of glyph or not), to provide the benefit as listed (16 Runic Power, 8 Energy, 4 Rage, or 1% Mana). If you do the math on this assuming you cast WG on the caster group every single CD, it provides ~150 MP5 to the raid (assuming 5 caster targets every CD), and even more if you're casting Rejuv on the raid as well. Personally I think it's quite a lot to get from 3 talent points, especially given it stacks with all other regen. Of course, it again depends on healing style and assignment, and YMMV.
Gift of the Earthmother: I only included 3 points in GOTEM in the 'core' spec as not everyone chooses to max out this talent. It could be due to having Celestial Focus and not needing as much from this, or it could be a choice to get other talents instead of saving that 0.1s (or whatever) for the HoTs. Again, you'll have to decide this one for yourself, but personally I think every resto druid (regardless of gear & assignment) should have 5/5 points in this.
From the above options, there are a few typical specs you'll see around:
The tank healer:
Focuses primarily on Nourish spamming with HoTs on the MT, along with WG being cast on him + melee.
The raid healer:
Focuses on improving HoTs & random raid heals, along with a bit of utility (Glyph of Innervate).
CF tank healer:
Swaps points in Tranquil Spirit for Brambles + CF, but you'd really need a lot of mana regen on your gear for this to be viable.
The HT spec:
Don't do this. You have to sacrifice so much in order to get HT up to Nourish spam sort of output, and the benefits really aren't worth it."
To add my two cents:
I use the "Raid Spec" exactly as Degrador has posted it, for reference. I think the other two specs are a fair representation of viable alternatives, although I personally would try to find points in the "Tank Heal" build for Natural Perfection to try to maximize Living Seed. Most likely I would harvest them from Brambles and/or Tranquil Spirit.
Improved Tranquility is a weak talent for raiding, but you can get a good deal of mileage from it doing heroics. Nothing wrong with speccing into it if you find yourself doing a lot of heroics in your early gearing. It's tolerable in 10 mans, but given that it only hits people that are in your 5 man party, you may find it missing some vital heals. Clearcasting into a Tranquility can provide you a nice period of regen time out of the 5 second rule, although I'd say this is more of a novelty rather than a core strategy.
If you read Degrador's descriptions carefully, you'll find there's a lot of "Meh" talents in the Druid trees. It's our cross to bear, unfortunately. After the "base talents" that Degrador posted, everything else is really just flavor. Any of the specs posted are perfectly fine for any raiding job and you can pick up and change jobs mid-fight without batting an eye. Even speccing into Nature's Grace for tank healing is not required by any means due to is more or less only being useful in a spamming situation due to its short duration. There simply aren't a lot of fights where that's required for more than a few seconds.
I would like to see somebody crunch the math on Celestial Focus vs Natural Perfection if they're so inclined. It seems like you are usually choosing between a piece of gear with either Haste or Crit on it. Celestial Focus gives the equivalent of 103 haste if I'm reading correctly. What does 3% crit work out to be?
Ok, I'm in an instance, now what?
Back in Molten Core, priests were king healers. In order to be effective as a druid, you had to rely on two things. One, you rejuvinated the crap out of the raid and hoped it would tick and pick up some healing. Two, you started casting your 3.5 second Healing Touch big heal (Yeah, yeah, Rank 4 was faster. Still glacial by today's standards) and either cancelled it when the priest sniped your heal or you prayed it would finish in time and heal for a crapload. Regrowth was ok for an absolute emergency but it was not to be relied on because it cost so much mana.
What was true then holds remarkably true now, to a degree. When you are raiding with a druid, you have full life ALWAYS. You are NOT 200 hp down because something sneezed in your direction. A good druid will see ANY change in life and immediately throw a hot. Hit Points ain't gonna regen by themselves, so you may as well put a HoT on and let them heal up. I've grouped with MANY healing druids that were perfectly content to let the dps be 10% or 20% down on life between pulls. There's no reason for this. Heck, you can toss the hot while you're moving between pulls. Druids are the most mobile healing class, take advantage of that.
Tanks should have HoTs rolling always. Before the pull, during the pull, heck, even after if they need to be topped off. Even if the tank is at full life, a rejuvination will pick up incidental damage they might be taking. It also leaves you open to Swiftmend if they take a damage spike. Rolling a 3 stack of lifeblooms on the MT is still common practice, although generally it's considered mana-prohibitive to do it for more than one target. Generally you'd expect the tank to have Rejuv, Regrowth, and a Lifebloom or 3 all ticking away for the vast majority of the fight.
We do very little cancelling of spells nowadays. It's sort of a shame, but healing is simply too fast usually. The idea of predicting the target to be healed it is still solid though. Because our heals used to take so long, we would try to guess who would be taking the next big hit and start to cast on them, even if they were full life. If the hit never came, we'd cancel and reassess. Being able to predict damage is still very valuable. I will very often put a HoT on a clothy before an AoE pull if I know they tend to pull aggro. That puts me into a position where I can blast a Swiftmend without waiting for a global cooldown (seconds count!). Predict who will be taking damage and cast accordingly.
Your 3 top healing spells will probably be Rejuvination, Wild Growth, and Lifebloom. Druid use almost all spells in their arsenal though. If you're tank healing for one reason or another, Nourish will probably take over for that fight, but really it's all about your hots.
Rejuvination is our workhorse. See damage? Throw a rejuv. Most of your global cooldowns will be on this spell. Last I checked it's our most mana-efficient spell for healing (assuming all ticks count, which is rare).
Wild Growth is our raid hot. It has some advantages over Rejuv. It hits multiple targets, immediatly starts healing, and is "Smart", targetting the players with lowest life. Generally you can use WG whenever you can use a Rejuv for more or less the same purpose. It does cost more, however, and is on a cooldown. It also doesn't last nearly as long, meaning you'll have to pay attention to the affected member that much sooner. The best use for WG tends to be when lots of people are taking damage (Derf Derf). Most of the time Melee groups are ideal for this because they're forced to clump together, but sometimes you can see a group of casters close enough to benefit. One trick to improving your results is to physically run yourself into a scattering of people an use yourself as a "Pivot". The range is 15 yards so you get a pretty good feel of where you need to be to land the WG on maximum numbers.
Lifebloom has changed roles with 3.1. Druids used to "Roll" lifeblooms on multiple targets, stacking the HoT up to 3 and never letting it expire. This provided about 1100ish hp per second per target and could be reliabley done on 2-3 folks, 4 if you were stretching. More than 2 was hard on the mana, but not unreasonable. Now they've changed the mechanics of Lifebloom. Its cost was doubled and it now refunds 1/2 on bloom. You get credit for each stack. This makes rolling blooms very mana intensive and impractical for any stamina-oriented fight unless the tank needs absolute maximum heals. The spell is not worthless, however. The Mana Refund does NOT take into account any discounts you happen to be having. That means single blooms are cheaper. This makes it a perfectly reasonable spell to use for "Touching Up" the raid. It may quite possibley be the cheapest/most efficient heal in our arsenal now (I'm sure elitistjerks have the numbers on this vs Rejuv somewhere). Casting Lifebloom off of a clearcast proc is very nearly a free mini-mana potion. Also note that Lifebloom is a very tactical spell. If there is regular, heavy damage that takes place periodically, you can "Seed" the raid with lifeblooms, trying to land the Bloom after the big hit. It's a great tool despite its naysayers. (Note: Because you generally want the Lifebloom to expire, the LB glyph is pretty much horrid now).
To clarify, it's not at all uncommon for the MT to have 3 Lifeblooms rolling and not blooming if you are the MT healer or if the tank is taking incredible amounts of damage. During 3.0 it was considered a "Best Practice" to keep 3 LBs up at ALL times on the tank, and most likely the OT and a few other folks too. During 3.1 rolling lifeblooms isn't as attractive as it was, although it is still effective and relatively efficient. It's perfectly legitimate, but I would maintain it's slipped from "Mandatory". I generally keep one bloom on the tank anyway for the Nourish benefits, and refresh or bloom as the situation warrants.
Regrowth has a very big following. I hate it. Well, I don't care for it. It's expensive and cumbersome. The main reason I use it is not so much for the initial heal, but for the nearly 30 second Swiftmendable HoT it places on the target. Generally, only tanks or people that are going to be doing a lot of kiting (and thus getting range issues) ever get Regrowth from me. Some folks argue that glyphed regrowth is king of the hill (The HoT WILL get the 20% increase), but I found it encouraged poor habits for me personally. Your mileage may vary. It's been generally accepted that Nourish is a superior direct heal for spamming.
Again, for clarification, regrowth is a legitimate healing spell. It has the longest running HoT you can get and heals for a reasonable amount initially, making it a fine heal for both tanks and the raid. I just find myself using it sparingly - mostly to keep the HoT up on the tank. Most often I can accomplish what I need with a Rejuv/WG or Rejuv + Swiftmend for raid healing. It's a preference, not a mandate.
Nourish is good, but not as much of a workhorse as you'd think. You really need at minimum one hot for it to be remotely efficient. Generally tanks get Nourish spam if they're taking heavy damage. Nourish is also an acceptable flash heal for things like Kel ice blocks. With the right gear/glyphs/talents, you can get some very, very high nourish crits. Generally used as a tank healing spell. Full T7 with Glyph makes for some powerful heals, but I worry what will happen as you change to Uld gear.
Tranquility is actually pretty good and shouldn't languish in your spellbook unused. It makes a great "Oh Shit" button if your group just took a ton of AOE or a whilrwind. You'll use it somewhat regularly in 5 mans. It can be expected to heal 4-5k every couple of seconds which is generally enough to pull a bad situation into a salvagable one. If you're doing a lot of heroics, putting hte 2 points into improved tranq isn't a terrible idea, as it allows you the option of an emergency button every pull.
Healing Touch is nearly dead now. It's used almost exclusively with Nature's Swiftness, and even then you'll find you want the NS to fire off an instant Battle Rez more often. Switfmend will generally do everything you need this to do.
Innervate needs to be seen as a heal for mana. I usually use it on myself if things have gone very, very badly. Sometimes I cast it on undergeared healers to keep them up and going, sometimes I don't use it at all. There's simply too many variables to tell you when to use this spell. Recent changes make it no longer regen based on spirit so now it's much more diverse. When in doubt, you can always ask on vent what to with it.
You really shouldn't need a mod to heal. Some folks swear by them and I know there is a segment of folks that think good healers will be even better with them. I'm skeptical.
Generally speaking, Blizz has implemented MOST of the UI stuff that mods used to provide. I have no problem healing vanilla. Additionally, I don't run into the problem of "My mod is broke, now what". I know Healbot gets used sometimes. I am half looking for a more efficient way of keeping track of hots, but I didn't care for Lifebloomer and haven't seen much else come down the pipe.
Recount is nifty for keeping track of what spells you're using most. Keep in mind that healing meters are not the end-all-be-all of healer quality (although it's gratifying to see your name up there every once in a while).
Degrador has put together a nice list of mods he finds useful.
"I'm fairly certain you'll find all of the resto druids who actually give mods a fair go will never go back to without them. Yes, you can heal with Blizzard's UI, but there is just so much you're giving up by doing so that you really are quite silly not to take advantage of them.
As for which ones you use, that's a personal preference. The most popular ones are:
Grid + Clique
Xperl (+ possibly Clique)
Personally I use Grid + Clique. It's got full tracking of all your HoTs on the entire raid (including indicators for when they're about to expire), and if you've got a 5+ button mouse you can easily map every healing spell you need to it saving your left hand for movement (+ modifiers for mouse clicks).
I believe Healbot can do most of this, but when I first used it I found it rather clunky and not as customisable as Grid. Some people may prefer not to go through such an in-depth configuration as Grid though, so it might be the better option to go for.
Xperl is extremely popular as a general unit frames addon, however personally I've found it rather lacking when it comes to healing via raid frames. If you just want your addon to look pretty, Xperl is very good at that, but for actually improving your effectiveness as a healer, I'd look to Grid or Healbot first."
Nuwalla also has posted some information on page 3 that expands on her experience with mods. It's definitely worth taking a peek at to see one example of a healing druid's UI.
Many people swear by and rely on mods. There's certainly no shame in using them. Try them out and see what you think. Just make sure you realize that they aren't absolutely necessary and you have a gameplan if they start to act up.
I feel that in order to be the best healer you can, you have to get used to using both the keyboard and the mouse together. I bind my Rejuv and Lifebloom spells to the Q and E keys, and then a few more spells (Like barkskin) to my 5-button mouse. The mouse I use to select targets. This gives you the fastest response time. Think about all the time you waste mousing over your target and then your action button. It's hard to adjust to if you're a clicker, but the results are well worth it and I can no longer imagine healing any other way. I do have a few spells that I have to click, but generally they're the longer cast ones, have cooldowns, or are just rarely cast.
Mana is your lifeblood. Do not run out of it, ever. When your gear is fresh, spend the money and get the mana potions and mana regen food. You won't have to rely on it forever, but often the person folks are most grateful to at the end of a boss is the healer that had enough mana to bull through the fight and keep the important people standing.
Learn to priortize your heals. Figure out who you NEED to spend your time on and who's...living by your good graces. The general rule of thumb is - Tank first, then Healer, then DPS.
Figure out your raid buddy. Basically, figure out who you're always healing with and get a feel for their style. Some long-term guildies have been healing together so long that we can nearly read each others minds. You get a feel for the other healers' styles and priorities. I know I can rely on certain peeps to keep a good eye on the tank, so I can concentrate on raid healing, stuff like that. Once you get a feel for each other's styles you'll notice things going much more smoothly. Look for where they position themselves. Do they cast group heals or single heals? What's their mana use curve look like? If I see this person out of mana in 2 minutes do I throw them an innervate or are they going to mana fiend in a second? Stuff like that.
We're in something of a golden age at the moment for Druid healing. Put simply, we're capable of either raid healing or tank healing, and we can really do both with one spec and one set of gear. In my opinion, we're slightly better raid healers simply due to our mobility and hots, but you'll end up doing plenty of both tank and raid healing any given night.
I have the mentality of being the "Fixer" for healing. I *can* provide fast emergency heals for spikey damage, but I really shine at keeping HPs up from the incidental garbage damage a raid always seems to pick up. My HoTs alone generally aren't enough to keep a tank up (That would require at least some attention direct healing), but they help smooth out the damage and buy time to make decisions. Most of my healing decisions center around how I can make other healers' lives easier. Raid taking splash damage? HoT 10 of them and focus heal on the ones who got brutalized. Tank life acting swingy? HoT them up and move into a range where you can put more direct heals as necessary. Kiter having trouble staying near his healers? Put a few long-running HoTs on them and hope they'll supplement enough until they're back in range of something big. Or you can always just heal the crap outta somebody that just ate a beatdown. We're flexible like that.
EDIT: Multiple times for various grammar and clarity issues. Proofreading is win :P