Checkout my soloing Crab Spec.

[Rulli]

I made this spec because I wanted to get more use of out of my crab and I never soloed with a tenacity pet before.

http://www.wowhead.com/?petcalc#0wzG0rMzMz

I picked everything that seemed important in keeping aggro and surviability. I ignored dps talents. The only thing I'm wondering is if I should take those 2 out of greater resistance and place them in cobra strikes. Faster attacking pet = more threat generated?

I don't plan on tanking him or anything like that, just want a good daily questing pet.

[Kimbald]

If it's for questing, I wouldn't take a crab necessarily.
Not that a crab won't do, but than you could say 'any' pet would do (which is true).

Best aggro on multiple mobs is a bear currently: swipe + thunderstomp.

best single target aggro is the boar: nothing grabs aggro like charge + gore.

As for the specc:
I would drop those 2 points in resistance and take
Intervene: since your pet WILL lose aggro, nothing like intervene to get it back at you.
Last stand: combine it with mend pet and you'll have a great life saver.

Depending on your gear, you could even consider RoS.
But frankly mobs at 80 don't have the time to hit you much. RoS is more the pvp thing.

[Dilomush]

I have heard that turtles are the best for soloing by far and am thinking of taming one and giving it a whirl.

I have a bear and a croc for pet tanking but use them all the time when I am not in an instance, unless I am pet tanking (which I want to do more of), then I use MM spec. MM by now is only for instances I am DPSing. I think of my MM as "business" and my BM as "fun."

Bears have higher damage and their AOE is 180. Crocs have less damage (but still good damage) but their AOE is 360 so they annoy a larger number of mobs at one hit. Outside of instances my croc is just plain the easiest ever to farm with because of his 360 but going up against some serious nasty or a small mob of nasties my bear is best. Usually I use my bear.

If you go with a tenacity pet, spec it so taunt is available, take taunt off of auto, and practice tapping it for when your pet loses aggro. Thunderstomp grabs it right off and a good tap of taunt when needed really does the trick. Taunt has a 2.1 min CD so you do not want it on auto. It is also a melee attack so think of it as such.

My BM spec is for pet tanking not soloing but I can tell you that I hardly take any damage with the combination of my tree and my pet's trees (for some reason my croc's tree does not show up on armory but my bear does). As long as I keep my pet healed and use taunt correctly, I just do not die. I love my tree and it is great for quests and all around soloing.

I am really not that savvy of a player so cannot break your tree down (I got mine from a site about pet tanking) but, if you want to check my tree out, the link is below the image in my sig.

Happy soloing... I love it! Soloing and pet tanking is da bomb!

[Lysah]

If you're soloing, why not go beastmaster for the extra 4 points? They can help maximize your pet even more, take all the talents you have and then add in cobra strikes or something. Plus, BM has a much lower threat generation than MM or SV, so you're even less likely to pull off of your pet. Your killing speed will be comparative with MM and SV if you're rounding up tons of mobs and AoEing them down, and you'll be able to more easily solo elites as BM.

[Camelstoe]

If its just for questing at 80 and not leveling i would say that most tenacity pets a roughly similar. Go with which ever pet you like the look of. I know from personal experience that even with a DPS pet most things are dead before they get to me anyway.