One of the lads at work has a Pi with RaspBMC installed and loves it
It (sort of) does what he wants, 1channel/primewire, live sports (when it works) and he is well pleased with it
I was thinking about getting one to experiment with SickBeard and create an NAS or find a way to plumb my CCTV into it but need to convince SWMBO that we really do need another box under the TV, looking at that pic above has given me an idea to hide it though, I could attach it to the back of the TV with sticky backed Velcro
I remember reading somewhere that you can build a radio using a Pi which would be rather cool