I went to a 3D Design conference at Warwick University this week and the keynote speaker was Daniel Simon. This guy is the guy the 12 year-old me wanted to be when he grew up. He says about himself "Daniel Simon designs sophisticated vehicle-centered dreams for imagined futures, pasts, and sci-fi worlds". Pretentious, I know, but basically he designs cars for science fiction. This is what I used to do at the back of the class in school, doodling in my notebooks, before the teacher yelled at me for not concentrating. I love this guy.
Anyway, the reason I'm posting this is he has a number of his pictures on his website available to download as wallpapers. See here:
http://danielsimon.com/wallpapers/