Or, How I switched an existing ubuntu install to arch linux without losing data, or rejoining my domain.
The official installation guide (https://wiki.archlinux.org/index.php/Installation_Guide) contains a more verbose description.
This guide has been forked from https://gist.github.com/binaerbaum/535884a7f5b8a8697557
I've successfully switched existing ubuntu and fedora installations to arch linux without data loss.