Personally, I find Frost to be the tank spec of champions.
The World of Warcraft Armory
Good stuff with a single disease rotation for extra smooth play and unbeatable aggro. I've tried Blood tanking, and found it more troublesome than it's worth for the EH, and with the nerf to HS, I don't think I'll try again.. Never tried Unholy, but I think I just might get around to it one of these days. Anyway, if your comfort zone is frost, don't let someone else's opinion change your playstyle. It's your toon. Frost DKs got a pretty decent buff in the last patch specifically because "Blood is the spec of champs" and ol' Ghostcrawler had to scramble to make frost "viable" again. I spec'd frost pre-3.1, and I'll stay that way until the dev team breaks it. lol GOODNESS I'm on some nerd rage today.
...Thoughts of a philosophical Death Knight...
If death is the inevitable end of life, is life the inevitable end of undeath?