Enlightenment is a window manager for the X Window System that is designed to be powerful, extensible, configurable and pretty darned good looking! It is one of the more graphically intense window managers. Enlightenment goes beyond managing windows by providing a useful and appealing graphical shell from which to work. It is open in design and instead of dictating a policy, allows the user to define their own policy, down to every last detail.
WWW: http://www.enlightenment.org/