Set a different desktop picture for each Space.
SpaceSuit is an app that lets you select pictures to use for different desktops. This was a feature supported by OS X Leopard, but later versions of Mac OS X have removed this customization capability. SpaceSuit restores that option, allowing you to have a different background image for each desktop. SpaceSuit was not available in the App Store for this review, but we downloaded it from several sites on the Web.