My favorite kata is usually whatever one I'm just learning at the time. I think right now my favorite is different though. I just started learning Seisan (thirteen hands) but I think my favorite is probably (drumroll, please) .... Taikyoku rokudan. I like the multiple blocks, and the shifting back and forth from horse stance to forward stance.
Any other favorites? Or kata you're just learning? Or think are especially cool? or are looking forward to learning?