Thank you everyone.
I ended up going with the Casio CTK 5000. It was only $200 including overnight shipping.
From my limited research it seems to me that Casio makes better lower-end keyboards. Also I figured if Yamaha puts crappy drums on the s910, I can't imagine what they've reserved for their PSR line. The drums I heard on the YouTube videos of the Casio sound quite decent.
[This message has been edited by chony (edited 11-03-2010).]