What wallpaper do you have on your computer desktop?

What wallpaper do you have on your computer desktop? Why?

I have a picture of my hero, Diogenes The Cynic, an ancient Greek philosopher. He chose to live a simple life by giving up worldly possessions and living in a tub. His theory was that the person who has the most is the person who is content with the least.

I made a logo of the biohazard symbol and embossed it on a dark red background. I like the biohazard symbol and I'm even thinking about a tattoo...