Hiya. I'm kinda new to the hole DK tanking thing, I have a frost, and an Unholy tanking spec. They both seem to be doing fine. But I just can't decide which to use. I like both specs aswell. Someone should look at my characters spec and tell me which is best to use Her name is Sophiie on Cenarion Circle.
All 3 trees make a viable tank right now for DK, you really have to keep playing and figure out which spec your more comfortable with. Personally I like Frost, for extra snap AoE threat with HB.