I assume you modded it, Smooth Groove? If so, check out the forums at
http://www.maxconsole.net for some handy tutorials on how to use emulators on your PSP.
I am afraid I can't be much help regarding PSP game recommendations. I mostly play emulators (CPS2PSP, MVSPSP, PicoDrive) on the thing.

I did, however, enjoy God of War, Final Fantasy Tactics, Street Fighter Alpha 3 Max, Outrun 2006, and Crisis Core.