While this won't be a complete answer, I would suggest you will be fine generally with any of the three main tanks (feral druid/warrior/pally). The trick is what group setup you need to make them effective for what you're trying to do. If you have tons of healing available, druids are highly effective for lots of things. If your healing is mediocre, warriors offer the highest damage mitigation and the prevention of the double-crit. If you want to do AoE farming, the paladin has the easiest time keeping lots of mobs focused on him (through consecrate).

So, really, your question is a mite general for the specific answers you're looking for.

Several raiding guilds are now using paladins for main tanks in Black Temple, so to say that warriors are the only thing worth using on anything worth tanking is obviously mistaken.

It is, however, well known that tanking gear is much better itemized for warriors versus paladins early on.