Using the right desktop wallpaper can have a huge impact on your productivity. Complex wallpapers, like photos, can be nice, but in the end, it makes it more difficult to distinguish and locate your icons, and files on the desktop.
I’m a fan of simple desktop wallpapers, even a solid color, will do.
But, my favourite wallpaper is xScope Grid from iconfactory. It is discrete, and doesn’t get in my way, but the grid makes it even easier to arange and organize the items I have on my desktop.