It was recently revealed that one of Windows 8's new features will be the ability of Windows Aero to automatically adapt the color of Aero Glass to match the desktop background, so, for example, if you set a background that's predominantly red, Windows Aero will adjust its color so your semi-transparent windows blend in with the new backdrop.
The good news for Windows 7 and Vista users -- particularly if you're the kind of person whose desktop changes with the weather (or at random intervals) -- is that this feature is available now for free. The tool in question is Aura, which was recently updated for a second beta release.
http://www.downloadcrew.com/article/21428-aura_beta