Mooh,you might also try Musician's Friend. They have a section of desktop wallpaper that is really fantastic with a new one each week.

Scroll down to the Fun Zone and click on desktop wallpaper, then click on wallpaper archive.There's some pretty good art there.

I haven't been able to refine my blue clicky thing ability to get you all the way there, but I can get you to the website.

rr