I've been using mine as a separate AV device that gets loaded from the media tab. I used the blu-ray template as I had already installed awkward TV on it (OK, I cheated and used http://firecore.com/
but you can also hack it yourself if you search on awkward TV) and the crystal HD card ($50) so that you can get 1080p from it. XBMC comes installed with the firecore version so I've been using the apple TV for blu ray movies and h264 files from mythTV that LMCE does not currently play through the XBMC player. This gives me a variety of video streams such as TWIT, TED, Bild.de etc. that are built in. Also found a stream from XBMC to watch what is going on in the Middle East through Al Jazeera English which is a BBC-based service and have to agree with Hilary that this is real journalism. Translating the remote to LMCE has been a bit challenging so I generally use one of the free xbmc remotes for iphone or android. If you got it for free, it is definitely worth using as a way to extend LMCE's media reach.
Hope this helps.