I'm using onboard optical to the 701 optical in. From there into my Steg K series amplifiers to a Focal Be (Tweeter, 3" mid, and 5" sub) front stage and a 40KX sub in the rear.
Currently I'm not running bit perfect. After USACi finals here in about a month and a half I'll be trying to finally move over to all tuning done via the PC.
WinAmp, by far.
The sound stage isn't compressed as much and tonal accuracy and ambiance are better.