Had to place a link somwhere to this awsome post by Derek Molloy, about how to resize the disk for a VirtualBox VM:
http://derekmolloy.ie/resize-a-virtualbox-disk/
If you install Ubuntu Desktop (like I did), reserve more than 8GB for disk space... This process is a bit lengthy and annoying, but Derek's post makes it a bit better with it's clear explanations.
