...
Kano - If the Unity interface is running X must be running? Perhaps my Solaris background is leading me astray there tho? - Linux experience to date is limited. Ultimately I intend running headless - I don't want or need anything more than ssh to connect.
GPU mining usually requires X (Unity is just an X display manager - xubuntu uses xfce)
Headless is fine, but X still needs to be running for cgminer to get at the GPU properly
As long as the machine boots into X that's what you need.