We have a few Audiophile fans here who pursuit Computer to Dac to HiEnd HiFi equipments (and digital crossover to the speakers too) and I am so fascinated for their sound performance.
Here is the source part he uses:
1. computer with a good sound card
http://www.lynxstudio.com/lynxone.html US$500 or even better
http://www.lynxstudio.com/lynxtwo.html US$1000
1a: with a good reading rom: Plextor.
2. with a good dac (a studio one)
http://www.lucidaudio.com/index.php?Show=216&Show1=&Show2=223
about US600