I like to play classes that I relate with most, and of all the games I've ever played no class has fit how I think of myself more than the WoW druid.
I consider the warlock to be the polar opposite of the druid. I also think the two make a great team, more than most other druid combinations (even though druids can team well with most any class). Rogues are also great. Funny thing is these are the two classes I hate the most!