My guild, and my realm in general, has a tank shortage. This is neither new nor unusual; in my experience, tanks have always been the most in demand on most servers (although that may be colored by the fact that my main is a healer). So I've decided to level a tank. The problem is, I've decided that a few times now, which means I currently have one of each tanking class languishing in the level 40 range somewhere: a paladin, a druid, and a warrior. And I just can't decide which one to work on, or even if I should bother as opposed to just waiting until Wrath of the Lich King comes out and I can get an instantly-level-55 Death Knight for a tank.
What do you guys think? What's funnest to level? What makes the best tank for heroics/early raiding? Which one should I drag out of Stranglethorn, kicking and screaming, ultimately into Outland and beyond?