Umm get the MC360 skin for XBMC
It's what I'm running on the xbox and it's sweeeeet
so i had to check it out, and it definitely awesome. runs a little slow on my box, but that's ok. it's almost exactly like the 360. even has my gamercard linked to it.
but definitely the best thing that i didn't know about before was the wide icons. i've spent most of my day at work finding, making, and organizing wide icons for my tv shows, games, and etc.
i mainly use my xbox to watch downloaded tv shows, and this definitely makes it easier to browse through all the shows i have.