Warning: I type a bit dense, so I tried to increase readability a bit, but it still might be a bit rough, I"ll likely adjust it later but hopefully it isn't too big of a deal, this is mostly a niche thing anyhow.
Hello fellow mages, first off I don't personal challenge mode experience myself (I'm actually looking for it). But I figured I would make a thread that will benefit myself, and other mages looking for a solid grouping of tips for mages in Challenge Modes. Also a good place for mages to discuss challenge modes in one area. I will try to keep this updated with consolidated tips gathered from posts here.
Edit 2/17/14 (it's been a while I've actually quit the game and come back in the time frame people have posted on this... makes me feel special...) Anyhow just adding some content I noticed:
Due to recent changes Mastery is obviously not the full blown tops due to it not affecting shatter damage %. So you can primarily stack Int, simply because at that low of an ilvl it should payoff (I don't have maths just my accumulation of experience and mage-ness during this xpac). However you can most likely stay with Haste if you're a raider, and/or have a strong group it very well may be negligible. (can be debated).
In terms of Frost Bomb/ LB/ NT I personally utilize FB because it hits the most targets, (as stated by a few posters old/new) trash is the biggest time consumer. Frost bomb is strong against multiple targets (look at Akrean's frost guide for examples on bombs vs multiple targets) Single target frost bomb isn't significantly weak enough in single target (reference akrean again) to make a loss for single target. And hell if you're that particular you can just swap (It's not going to be that much of a deal breaker imo).
In terms of glyphs I would utilize Icy Veins (haste is good but the ice lance cleave translates a bit more with the damage modifier ((essentially what it is just in odd terms)) versus haste). CoC, a shatter CoC is pretty strong and if well timed can lead to some smexy burst (FB detonation synced with a pet nova and CoC = numbers!!!) Finally Ice Lance cleave glyph because it actually hits like a truck and makes a huge difference if for some odd ass reason you haven't noticed.
Minors really don't matter, except that I'd recommend that just about every mage use momentum glyph simply for its awesomeness, I do not think I could use regular blink ever again.
Blazing Speed or Ice Floes I say these two for their mobility BS gets your places fast (duh) and Ice Floes just allows typical movement while maintaining your dps (real obvious but does take some adjustment time). PoM is technically a dps increase but I find it so minimal to not really be worth it as frost, where the movement bonuses provide a greater advantage.
Personal Choice for TS, IB or FG. Simply its preference only thing I would mention is that IB takes a GCD which can make a difference if you're cutting it close, it's surprising how much it can add up where FG is entirely passive and TS is of the GCD.
Frost Jaw if you know you'll need that silence, ice Ward otherwise. Ice Ward be be applied to your tank, or anyone else, it essentially can become an extra nova for you.
Ginvis, greater survivibility, removes need for invis pots. That said if invis pots aren't an issue Cauterize isn't a half bad choice due to it being passive. Also for GInvis you have to be wary of your usage with it and when your Invis pot section is coming (might be worth having a few just in case for whoops moments).
Bomb tier see above
Invocation, it's just so far above the others and after using it so much as annoying as it is, there are strong times to use it that won't affect time too much, right after combat (trash pack is dead/one left/everythings 10% or less start casting it use blink to catch up etc) or before a boss is a strong time to utilize it. Incanter's Ward just lacks the punch at this point, and RoP is too restricting.
Frost is the best spec according to experienced mages
Reforge to optimize for the challenge modes, raid optimization isn't fully optimal for challenge modes. (Preference between having better offensive stats for trash but maybe missing a bit on bosses, but hitting harder on trash. Bosses are standard raid level of 93, so 15% hit or trash which typically level 91)
Also keep in mind that set bonuses and sha-touched gems are disabled in challenge modes.
A general guide with video links for general guides to each dungeon itself
Credit(People who posted valuable info in the thread which I edited in): Citrique Davey Niai Literally anyone who has posted in the thread I have gotten something from.