One thing that adds quite a lot of wow is that XBMC has its own http interface. Assuming you have a wireless network at home and an iPad or iPhone say, you can use that device as a remote control when viewing pictures and videos with XBMC. All you have to do is enter the address http://192.168.1.67:8080 (and bookmark it) in the browser of your iPhone and you'll see this:
That's a remote control with arrow buttons, enter/ok, back and home button. There are volume control buttons, play/pause/stop and some more.
Ubuntu + XBMC is very attractive visually and works perfectly!