Hi - a late reply!:

GNOME 3's Mutter and xmonad don't play nice together, so in the past xmonad users have always used GNOME's fallback mode (i.e. Metacity). There was some brouhaha when GNOME announced they were going to drop fallback mode due to lack of support, but after a lot of complaints they reversed that decision.

That is not quite accurate - yes there is a "GNOME Classic" session with 3.8 but it is not fallback mode ie it requires 3d graphics like regular gnome-shell: so basically gnome-session seems to assume 3d now.

In fact Classic is just a modification of gnome-shell using various extensions to make it feel more like gnome2 or fallback mode.

In either case, I've always used xmonad in conjunction with GNOME 3.x in the past but the latest upgrade to 3.8 has broken the configuration. Entering the desktop leaves a broken state where the thing visible is a grey background and a black bar where the top panel should be.

You can use XMonad with MATE if you like (a gnome2 fork).

Anyway things are only going to get more "interesting" with the coming move to Wayland replacing X11.

It would be cool to rewrite xmonad as a wayland/weston compositor or at least to write one in Haskell - probably first a binding to libwayland is needed I suppose.

Jens