Why not change things up a bit every time your PSP boots or VSH is reset... All you have to do is install and activate Y.K's Wallpaper Changer, fill up your memory stick with background images, and now it's a different experience each time, every time. WallpaperChanger randomly switches up the XMB background from the jpegs found in ms0:/PICTURE/Wallpaper.
WallpaperChanger is compatible with PSP-1000/2000/3000 and Go models. It's also compatible with firmware 6.00 up to and including 6.60. See readme.txt for more info.