I recently upgraded to a new wireless router and was looking for a password that is easy to type into small mobile devices but is also hard to crack.
I came across an excellent online utility written by Bart Busschots, the xkpasswd secure memorable password generator. It comes with presets for many common use cases including WPA2 and is also customizable. You can tweak the parameters until you get a high quality randomly generated password that will work for you. Check out the comic pane at the bottom of the page – it explains the concept.
Update: A further discussion of the concept.