I've been frost my entire career as a DK, but recently (and to be honest I can't recall the threads in particular) I read that after a certain amount of avoidance that you should spec Unholy for a better return from Bone Shield.
Also I'm curious on where I can improve stat wise (minus the obvious 25 man gear) and optimize as a tank. Any helpful/useful critiques would be greatly appreciated.
Frost, Unholy, Blood, they are all alike with some differences.
Mostly a matter of personal taste, there are some things like sarth 3d where single specs truely shine, but for "everyday tanking" everything is fine as long as the basis is 5/5/5 and some 60s cooldowns are in there.