Openbox

Openbox 3.x is a lightweight window manager for the X Window System. Openbox is historically similar in behavior and function to the Blackbox window manager.

Notable features:
 * Openbox can function as a standalone environment, or serve as the window manager for your Gnome or KDE desktop environment.
 * Root pane menu is customizable via a configuration file.
 * Keybindings and mouse behavior are customizable via a configuration file; reasonable default behavior is provided.
 * Multiple desktops.
 * Openbox satisfies both ICCCM and EWMH compatibility.
 * Xinerama multiple monitor support is provided.
 * WindowMaker Dock applications and Afterstep Wharf applications are supported.

A GUI configuration tool, ObConf, is available at: http://icculus.org/openbox/obconf/.