For raids, I’d go with blood or frost.
Here are my posts with much more detail.
Gravity’s Grid of Blood specs 3.3.3
Interactive talent tree to explain each talent
|Frost 3.3 spec here or dual-wield||Unholy tanking 3.3|
Unholy should not be used for maintanking most of the ICC raids bosses: its bone shield uptime is just too short. Exceptions are Sindragoa and Valithria (where it’s awesome). There is a “fun” argument for Unholy, but I cannot recommend using it for raids.
For 5-mans or raids outside ICC, any tree will do the job if you’ve more threat than your dps, and unholy is a great option for AOE. For 5-mans, I’d recommend Frost though, it’s easy-mode threat.
Which spec if unsure? More discussion on the differences here.
Want to talk spec?
pwnwear now has forums.
Very active and growing. We don’t do “rate my spec” yet welcome padawan tanks along with scarred old vets like me. It’s a meeting place for DK Tanks. Registration is fast; you have to pass a fun Q&A test on WoW!