AfterStep

best wm for unix around...
only ones on par with it are fvwm, enlightenment and litestep (allthough windows only) anyway...

incredibly flexible, and lightweight while
offering more features then almost any wm
out there...
and a very friendly and patient developer crowd..

My favorite wm/de for linux period. Afterstep just looks so crispy and is also very clean. It runs so smooth and is very responsive, along with almost umlimited configurability you really can't go wrong. My motto is Create your own desktop use AfterStep.