if you can afford it you have to buy the 3ds. the graphics are better then the wii and there will be alot of games comeing out for it soon. psp is way better the the ds and dsi tho. plus you should hack your psp, then you can get all the games for it free. good luck brotha!
i think the ds lite. i have a ds, ds lite, and a 3ds and my best friend has a psp. he doesn't like any of the game on psp but he loves the game on the ds Systems.
Neither hand held device is capable of creating it's own games, but The DS tends have have games of a more whimsical cartoon manner while the PSP has a broad array of games, but is considered more hardcore.