Okay a few things about the psp versus ds. The psp slim has double the memory of the psp phat;(64 MegaBytes of both ram and rom). The original psp phat only had 32 MegaBytes. The psp has a very powerfull processor compared to the ds and can easily run emulators and 3d games. Something the ds isn't very usefull for. The ds on the contrary has a touch screen so you can play some games on it that you couldn't play on a psp. As well as the certain nintendo specific games. The game boy ds is great at 2d games and very lmiited 3d games mainly due to not much memory ;(12 MegaBytes). With slot2 ram expansion pack you could add 32 MegaBytes of memory, but the 3d hardware is still very limited as well as the main processor. So it really depends on what you want. If you want a fast powerfull system capable of playing 3d games and emulators very well get the psp. If on the other hand mostly 2d gameboy type games are what you like go for the ds.