Now, the next step is avoiding the intensive EMI found in computers. The best way to do this is the perform the D/A conversion outside the machine. Use the digital output of the sound card and feed it into a seperate DAC. Optimally, a stand alone unit, but a good reciever can also do the job. At this point, prices can really go up though...and only worth it if you have the amp and speakers to match.
M-Audio Sonica Theater @ $120 acceptable to the audiophiles? I may get this myself if my nForce sound hardware doesn't start behaving soon.