Absolutely Free Backgrounds
This is an awesome site for quality free backgrounds on the internet. There are many categories that are all organized on an easy to access pull down menu. Some of the sections include business, classic, artistic, general, and more. Nice site! 

Free Themes
FreeThemes.com is your one stop for free desktop themes on the internet. It puts everything in categories as to where you can download entire themes, various screen savers, cursors, wallpaper, etc. Once you enter one of their outstanding categories you get more choices so you can easily find what you are looking for. Free Themes also has a server in your country and region so you have fast download times and the server isn't busy. This is a great site for desktop themes and everything that goes on your desktop. 

Desktops Unlimited
This site offers much more than just desktop themes. As some other desktop themes sites they offer both desktop themes, screen savers, wallpaper, and more. Their desktop themes section is oustanding. Instead of just listing all of their themes they distribute them in categories such as movies, music, cartoons, and other. This is a great site for everything related to your desktop! 

Amazing Screen Savers
100's of free screen savers including celebs, sports, and more! 

The Screensaver Gallery
This site tries to give information about screensavers, by displaying pictures (datails or full screen) of the saver 

Screensavers free
The best dedicated screensaver site on the internet. There are over 1000 completely free screensavers to find here, 

Ezskins
Are you not happy with the way your desktop looks? There are hundreds of ways to modify the look and feel of your PC and this site has them all. EZskins offers loads of free desktop themes. Categories include animals, cartoons, horror, religious, sci-fi and more. You'll also find "SurferThemes" (to customize your browser's appearance), as well as ICQ skins, which let you customize the appearance of this popular chat program. 

Cinema Desktop Themes
http://cinemadesktopthemes.com/ 

Top 50 Theme Sites
If you can't seem to find a great free desktop themes site than you may want to try the Top 50 Theme Sites. They offer a great selection of various desktop themes sites for you to go to. It is one of the best free desktop themes links sites on the internet today!