You can easily make any screensaver on your Mac into a wallpaper. Open System Preferences, Desktop&Screensaver. Choose the screensaver tab and select the screensaver you want to make a wallpaper. Hold down "Command and Shift" then press the Test button to activate the screensaver. While still holding down Command and Shift press the number "3" key. A screenshot will be taken of the screensaver and put to the desktop. Move it to the pictures folder. Now you can choose it as a wallpaper in System Preferences.
Personally I think the iTunes album art makes a horrible wallpaper because you can't see the desktop icons or the dock very well.