I prefer Frost spec for it's versatility, I've considered Blood, but I like frost's AoE capabilities and mitigation. Never tried Unholy, mostly cause I don't like the idea of keeping Bone Shield up and I don't know how it'd play with my gear.
Right now, I'm gemmed/enchanted for effective health and I eat hit food for my low hit rating.
Also, any inputs on gear to get would be appreciated. I'm looking to upgrade my cloak to the valor emblem cloak when I get enough emblems. Also, I'm looking to get the boots from Noth in Naxx 10 or Thaddius in Naxx 25. Naxx is my best source for gear right now, don't get into Ulduar much.