So I just sold my Nintendo DS, and got a Sony PSP, which is freakin awesome!!
If you're in the handheld market, don't even consider anything but the PSP, the screen is huge, the colors are vivid, and believe it or not, FIFA 2006 seems like the exact same game as the one on Xbox. The processor they are using is incredible! Not only that but it plays movies, music, multimedia.
I've played FIFA, and I own Untold Legends (like Diablo 2 - amazing game!) and Burnout Legends (best racing game ever!!)
Any interest in handhelds?