Window Managers

What kind of WM do you use on your Linux-based operating system?

I use AwesomeWM because it's simple in configuration and easy.

scrotwm(they renamed it to spectrwm now) on FreeBSD

I use scrotwm because it's fast, easily modifiable because it's written in good ol' C. And conf file is easy (you don't need to know Haskell like with xmonad)