My opinions on Microsoft’s Bing services vary, but one feature that I am in love with is included in the Bing Desktop application. It allows you to adopt the current day’s Bing.com background image to your own desktop. The images range from lush global landscapes to beautiful macro images of flora or fauna. And it can automatically update every day for a complete change of scenery. For that feature alone, I think it’s worth an install.
If photo-based desktops is not your thing, then on the other end of the spectrum is SimpleDesktops.com (new window). Here you’ll find minimalist desktops in a broad range of flavors. My current desktop is title “Eiffel”. Definitely check it out.