Originally Posted by
tyggyr
Frost has rather better AoE tanking; chances are people will be just barely more tolerant of you as a new tank than as blood. There aren't any gearing differences between the two specs (other than weapons of course); you could get a 2h mace crafted for blood, but personally I don't think it's worth doing.
I have to say, though, I hope you're really thick-skinned because new tanks are treated like trash in heroics these days, and DKs have it worst of all (somewhat deservedly, as newer DK tanks tend to be pretty tough to heal - but not the way 99% of the healers today are geared).
If you do tank, and people start giving you grief, just say "If you'd prefer, I can drop group and you can wait for another tank, or you can let me tank at my pace" - this should shut most people up; if it doesn't, drop group and go to a quest while waiting for your debuf to wear off, earn some cash. Chances are you'll get into your next dungeon before the obnoxious group gets their next tank....