Cut the Rope and Unblock Me are the best I've found so far. I really like puzzle games. I don't care much for Angry Birds and such. I really enjoy Draw Something as well.
Magical Drop Touch is fun, but some people may not like the controls. There are 3 different touch options, and I find option 3 with controlling left-right with one thumb and the up-down with the other works the best for me. Someone made a Chu Chu Rocket clone too, but it lacks the charm of the original. Sega needs to get on making a true mobile version.