I have now been using my Squeezebox Boom music player for about 6 months and really love being able to access all my iTunes music library without my computer. It also doubles up as a radio as it can also stream internet radio stations.
The sound from the Squeezebox is good and its easy to find playlists (though not as easy to set them up on the music server).
Rather than set up the music library on my laptop, I invested in a home server for about £150. This also acts as a backup for music, photos and other files.
I was going to buy a similar squeezebox device for my sitting room, however withe the launch of an improved and cheaper Apple TV device which does the same (and more) for less I think that is what I will get instead.