The Hauppage MediaMVP is a cool little device, runs linux under the covers and can be connected to your TV/Hifi to stream music/video across your network from a file server. A NSLU2 makes a perfect partner as a file server to the MediaMVP.
More info on the device here: http://www.hauppauge.com/html/mediamvp_datasheet.htm
For more fun check out MVPMC below.
MediaMVP Media Center (MVPMC)
mvpmc supports playing audio (mp3, ogg, wav, ac3) and video (mpeg1, mpeg2) from MythTV? or ReplayTV? digital video recorders. It can also play audio and video via HTTP, NFS, and CIFS. It is capable of playing internet radio via SlimServer?. It can also display images (jpg, bmp, png) via NFS and CIFS."