I've been using a Zoltrix (http://www.zoltrix.com/)  Nightingale Pro
soundcard (cmpci driver) and running coax S/PDIF from the computer room to
the livingroom (about 50' of cable run, over cheapo speakerwire).

Sounds great; no hum, no hiss.  T'was about $50 off ebay (it was hard to
find a source for it).

    ScottE