Desktop themes are the visual background, wallpaper, sound, taskbar, icons and other elements that you see on your desktop. Using the default desktop is good but not good enough if you like to see and hear new desktop elements.
WindowBlinds is the most popular application to change the way your desktop looks. You can choose from several desktop theme categories such as computers, food, games, holidays, nature, music, people, places and many more. Some of the desktop themes are free, as long as you are using the WindowBlind program.
An example of WindowBlind that I applied on my Vista desktop is called "Sabertooth": It does not affect the performance of the computer even if I change the visual effects, wallpaper, fonts, transparency, colors, style, and textures. What is neat is I can continue using any desktop background that I have when the new WindowBlind theme is applied.