First things first, your third build will suck. Frigid Deathplate's a good tanking talent but to reach it you're throwing 15 points in frost that are all fairly useless. Except Frigid Deathplate and Toughness, nothing you've picked up in that tree will really improve your tanking. As it stands, what you've got in the frost tree is an odd variant of a PvP spec.
Then, to answer your question: frost would be better for survival, blood for single-target tanking and unholy used to be the king of AOE tanking - I haven't seen it into play since the patch, but apperantly it still is.
If it helps,
here is my current blood tanking build. The reason it looks like it does is because A) I'm not a fan of Rune Tap in a tanking build, it feels like I don't really need it, B) It's focused mainly on heroics - I'll swap around some points when/if I get into raids and C) Currently, I prefer having the utility of things like Hysteria, Epidemic and Bloodworms over anything else I can currently pick - I'm not doing hardcore endgame so while the 6 points won't make too much of a difference statwise they will simply make life a lot easier for me. That said, I could probably grab DRW and do some decent DPS in the same spec as well, but I don't quite feel like I need it yet.
Aside from all that, just some random things:
-Get rid of Mark of Blood. I used to think it was alrightish, but just think about it. How many bosses (raids and heroics) actually hit you in such a way (quick low damage melee blasts) that Mark of Blood would make a difference when used on them? In Ulduar for example, there is *one* such a boss which hits so hard that the 4% heal isn't going to matter anyway since 2 seconds without heals kills you.
-Ask yourself if you need Scent of Blood. I've never ever picked it in any tanking build because I rarely find myself out of runic power. Is it worth dropping those 1/3 points there?
-Same thing for Rune Tap. If you really focus on heroics only I guess it might be more useful than in raids, but still - look up the average heroic boss and see how Rune Tap would fit into that fight.
-Get rid of Imp Blood Presence. You tank in frost presence (shamefully), and 4% healing on your damage done equals at most something like 100 hps. That's just not ever going to save your *** or be useful at all.
-Last but not least, drop Unholy Command. It's a PvP talent, nothing else. You've got another short-cooldown taunt next to Death Grip, if a DPS manages to outaggro you so bad you need 3 taunts in a row to keep the mob on you either you are or he is doing something completely wrong anyway.
-Consider Might of Mograine, Sudden Doom or Bloodworms for threat, and Ravenous Death for the little statboost.