Pastelish is an excellent theme for those that like Fall tones. It is a basic theme that only has minor modifications such as the staus bar colors, the minimize, maximize, and close buttons, and other basic elements. If you want to just touch up your desktop a little, pastelish is for you.
Use on Windows Vista: Vista Ready. (see help tab if you have issues)
Use on Windows XP : Download and install Theme-Patcher (Instructions included).