I first tried XMonad about a year ago, and its since become an indispensable part of my standard Linux setup. It's an incredible productivity booster, especially on dual monitor setups, making it infinitely easier to rapidly switch between multiple windows. It makes me weep a little inside each time I have to boot back into Windows' single, non-tiling, keybinding devoid workspace (on a side note, I've used both DisplayFusion and UltraMon with some success for a more keyboard focused experience, so it isn't all bad. Still...)

Now, I either lie in the segment of Ubuntu users for whom XMonad does not work out of the box, or the segment of Ubuntu users for whom XMonad does not work out of the box and who need to head to the interwebs to figure it out. Since I also end up (re-)installing Linux on VM's, or my laptop, or the lab computer once every 4-5 months, and forgetting the solutions I'd arrived at previously with astonishing punctuality, this is a less than ideal scenario.

So in the interest of documenting this for my future self (and anyone else who might find this useful) here are the steps to get XMonad to work on your latest Ubuntu install -

1. Install gnome-panel

$ sudo apt-get install gnome-panel

2. Install XMonad

$ sudo apt-get install xmonad

3. Create your xmonad.hs

This one tripped me up for a while, but I realized I suffer from this bug every time. I haven't figured out why, but the fix is pretty simple. Just, create a (possibly empty) xmonad.hs like so -

$ mkdir ~/.xmonad
$ touch ~/.xmonad/xmonad.hs

4. Replace your default mod key

I like replacing the mod key from its default of Alt to Super (the Windows key). If that makes sense to you, you might want to edit your xmonad.hs with the minimal -

import XMonad
import XMonad.Config.Gnome

main = xmonad gnomeConfig
       { modMask = mod4Mask

5. Reload your xsession

Log out of your current session and log back in using the 'Gnome with XMonad' option.

And there you go. Five incredibly simple steps to a vastly improved dual monitor experience. Happy hacking!