Onyx64-Ubuntu Unity Derivative
Onyx64 has done honours to Unity desktop and in 2.1 Gib it has picked everything including XBMC.
Only missing thing is Ubuntu One Cloud facility.
It has messed up a bit with workplaces but I could open four different applications and freely pick and drop into any of the four available workplaces.
One has to double-click to get to full view and one cannot close an application when they are in workplace mode framed down since the mouse cannot locate exit button.
it has compiez which nice graphic effects.
XBMC freezes the mouse in exit mode one has to wait few minutes till it exit completely.
It is a Gentoo derivative but if you want to use it download Sabayon and install only media center for use.
It takes an awful lot of graphic memory that is why it freezes.
Overall if you want to Unity experience this one is for you.
If you want XBMC go for Sabayon.