Xmonad on Natty Narwhal is a snap to set up. Just install xmonad 0.9.1:
$ sudo apt-get install xmonad


Create a config directory:
$ mkdir ~/.xmonad


Create a new config:

$ vi ~/.xmonad/xmonad.hs

import XMonad
import XMonad.Config.Gnome
import XMonad.Layout.NoBorders
main = xmonad
    gnomeConfig {
            modMask = mod4Mask
          , layoutHook  = smartBorders (layoutHook gnomeConfig)
    }

Compile (if/when successful, end with “:q”):
$ ghci ~/.xmonad/xmonad.hs
:q


Create the Gnome session files:
$ sudo vi /usr/share/gnome-session/sessions/xmonad.session

[GNOME Session]
Name=Xmonad
Required=windowmanager;panel;filemanager;
Required-windowmanager=xmonad
Required-panel=gnome-panel
Required-filemanager=nautilus
DefaultApps=gnome-settings-daemon;


And desktop:
$ sudo vi /usr/share/xsessions/xmonad.desktop

[Desktop Entry]
Encoding=UTF-8
Name=XMonad
Comment=Lightweight tiling window manager + Gnome
Exec=gnome-session --session=xmonad
Icon=xmonad.png
Type=Application
X-Ubuntu-Gettext-Domain=gnome-session-2.0


Then when you log out, enter your user name, select “Xmonad” from the bottom menu (as opposed to “Ubuntu”, “Unity”, or “Classic”), then enter your password, and enter. Note that I set the meta key to the “Win” key which seems to be most compatible with Gnome. See the previous post for the basic dozen Xmonad commands (here are two: Win-Shift-q to logout of Xmonad and Win-Shift-Return to open a terminal window).