Hey! Interesting thread, thanks for starting it. I would post my background picture...but I run Windows 7 Ultimate and use all my "keepers" in the desktop slideshow feature....set at 10 second intervals...
This is mine at work, on my cellphone front and back, at home on my PS3, and a slightly different at home on my PC because I use a dual monitor setup. (I have right screen with horizontally flipped purple background.