These are my favorites. I use 4 different wallpapers depending on what time of year it is, however with the new windows 7 rotating wallpapers I'm slowly adding more to the repetoire.
As you can tell I'm a big fan of oil paintings and video games
looks like a How-to needs to be written for this one. It's simple tho.
Windows 7: 1 - Press Win+D (clean screen) and Right Click on Desktop and Click Personalize 2 - Click Desktop Background Link on bottom of screen 3 - Put a CheckBox next to all the images you want to rotate 4 - Set the Picture Position and "Change picture every" at the bottom of the screen (I also click Shuffle) 5 - Click Save Changes