Prices for new/refurbished iPod Touches. I'd like to use one as a sort of handheld game device.

4th gen 3rd gen 2nd gen
64gb $400 $320
32gb $300 $230 $210
16gb $190
8gb $230 $150 $150

Resolution comparison:

iPod Touch 4th gen 960×640
iPod Touch 3rd gen 480×320
PSP 480×272

Okay, true, the iPod doesn't have an adequate controller interface. Boohoo.