Some games people haven't mentioned that I've liked quite a bit:
Loco Roco, Twisted Metal, Wipeout Pure, Castlevania Dracula X, Brave Story, Puzzle Quest, Metal Gear Portable Ops, Killzone Liberation, 2 GTAs.
And I can already think of four games with a lot of potential for next year:
God of War, Crisis Core: FFVII, Wipeout Pulse, and Patapon.
I'm personally incredibly satisfied with the system so far, and the future is looking quite bright.
My Top 5:
Shadow of the Colossus, Metal Gear Solid 3, Shenmue, Skies of Arcadia, Chrono Trigger
My 2 nex-gen systems: PS3 
and Wii 
Prediction Aug '08: We see the PSP2 released fall '09. Graphically, it's basically the same as the current system. UMD drive ditched and replaced by 4-8gb on board flash memory. Other upgrades: 2nd analog nub, touchscreen, blutooth, motion sensor. Design: Flip-style or slider. Size: Think Iphone. Cost: $199. Will be profitable on day 1.
