I think we're still left with the conundrum of not having any suitable software to run on a DIY system. I just revisited the XBMC web site - they have no clear vision of what their project should look like, instead hosting horribly designed skin after horribly designed skin.

Don't get me wrong, some of the skins are pretty, but the concept of "skin" is apt, because the initial beauty is only skin deep. None of them are thought out well enough to feel like they were carefully developed and implemented as part of a complete finished product. They're all just gloss, and IMO, even half-decent UX is lacking in all of the ones I've seen listed. They're all variations on the same bad idea.