I've been toying with NOVA, a FPS, on my Captivate.
It's not super easy to play or anything, but I'm pretty impressed they made a working high end style FPS on a phone. I would like to see more of this since FPS is my favorite genre. The GPU in my Capty is supposed to be quite powerful, (moreso than Droid X, Evo etc), so I find myself wondering how much better a FPS that really pushed it could look.
Although, there's so much auto aim and such to make it playable, sometimes I wonder if it's really not just a glorified light gun or on rails game or something, more or less.