> sudo cabal install xmonad xmonad-contrib
Then you can get dmenu or dzen for a small menu and trayer for a small system tray.
Then use a premade config file from here: http://www.haskell.org/haskellwiki/Xmonad/Config_archive and mess around with it.
To learn the keybindings, print this out or make it your wallpaper: http://xmonad.wordpress.com/2009/01/19/xmonad-cheatsheet/
For them ubuntu users, if oneiric broke a lot of things you can follow this: http://markhansen.co.nz/xmonad-ubuntu-oneiric/ That should allow you to select an xmonad session as opposed to a unity one during login.
As a general rule you can simply use xmonad as your window manager and just launch gnome-settings-daemon (or was it gnome-config-daemon?) to get all the theming, font antialiasing, etc. If you run nm-applet manually, that should launch the networking stuff (if it didn't already). I haven't tried using xmonad with the ubuntu panel and stuff, so I don't know about that.
Edit: I use this one: https://github.com/vicfryzel/xmonad-config
It works great with multiple monitors, alt+w and alt+e move focus between monitors, and then I can swap which workspace is in which monitor really easily to move things around.