XFce is an easy-to-use and easy-to-configure environment for X11 released 
under the terms of the GNU/GPL license, based on GTK+, with pulldown menus 
and color icons, 3D widgets, etc. 

XFce features now a set of applications including a powerful Window Manager 
xfwm, a toolbar/application launcher, a backdrop manager, a system sound 
manager for X11, a user friendly  interface for mouse configuration, a 
pager providing a miniature view of all XFce desktops, a clock/calendar 
and at last but not least a filemanager, all sharing the same look'n feel.

WWW: http://www.xfce.org/