Honestly, play what you want to play. Any of the tank classes can get the job done on any fight in game. Ignore the forum QQ about whatever tank is supposedly at the bottom at the moment.
If you need to quickly reach 80, a DK does essentially start in Outlands. If you already have each class at or above 60, then you might just want to look into how each class tanks and see what fits you.
Paladin tanking feels pretty rigid (to me at least) in the sense that you follow a fairly strict rotation.
DK tanking flows in cycles (assuming a predictable fight) based on rune refreshes.
Warrior tanking is about watching procs and reacting accordingly. It is probably the most demanding in terms of attention span.
Hope that helps somewhat.