I just bought a 8gb memory stick for $55 at amazon. 4gb are only $25 now. There's also a PSP bundle coming soon with 4gb stick in the box plus some extras for $199. 8gb is amazing! I just put Crash 2, Twisted Metal 2, Destruction Derby, Jet Moto, Street Fighter Alpha, Hot Shots 2, Suikoden II, Beats, and Jeanne D'arc plus some custom firmware software and still have 5.4gb left! Granted all those games aside from Jeanne D'arc and Beats are relatively small PS1 games, but that's still a pretty awesome set of games to have on board without UMDs.

I'm calling it right now. PSP2 out next Fall. No UMD drive. 8gb on board memory with memory stick expansion slot. You heard it here first!