@JamesMorrison,
I know this is a discussion old as hell but since I've been going through your interesting topics to tag them I noticed it.
You may also want to try a Windows Media Center and/or a Media Center Extender. The Media Center is like a TV version of Media Player with TV abilities but also the interface to use in a living room, and not a computer.
With an extender, you can network the content (wired or wireless) and stream the music to the extender. So you could have a computer with all the music streaming it to the Media Center Extender in the living room, or just put a Media Center in the entertainment center (mine just broke down after years of abuse, but I usually replace the whole home theater rack with one media center (plus the TV and speakers of course).