From what I've heard, the Samsung Galaxy S should have the best graphical acceleration of any phone currently available. Unfortunately it seems Android has some other limitations that prevent the same level of gaming as you get on WebOS or iPhone. I heard it has something to do with not being able to run apps from the SD card, which limits how big anything can be, but it has to go deeper than that too.
And I don't even like Apple or the iPad, but if I had two hours on a bus/train every day, I'd totally get one. It seems like exactly what the iPad was made for.