I've been using a Pi running XBMC for about a year. It's connected to a big hard drive. I can copy stuff there from my laptop (movies, music, etc.) It works pretty well; I don't remember having to "service" it in any way since I plugged it in.

It works fine to stream stuff from YouTube, too. Shows for kids, etc. The XBMC remote on my phone is pretty handy too.

Overall, I'm pretty happy with it.