I have the HTC desire running android. There's emulators for all android phones so I highly recommend buying any phone running android however if you want to game don't get a touch screen phone. It's not responsive enough or accurate. I recommend getting a touch screen with a qwerty keyboard, this is your best bet by farSamsung Galaxy S
Android phones right now is HTC Desire vs Samsung Galaxy. From what I remember the desire had a better CPU but the galaxy had a better GPU making it superior for gaming (I saw a vid with it running quake 3 quite easily).Samsung Galaxy S Pro
Did I mention the emulators are free? But you need to pay for them if you wanna save your game(roughly $2-5 each emulator, not rom). Bargain.