I don't make my computers, but this is what I have had done.
If you have a little more money to spend, try the Digital Audio Labs with aes/ebu or cheaper spdif. It outputs at 44.1 24/96 and not the dvd output (of 44.7?), like a lot of the soundblaster products. I have tried the 2 most expensive ones available eighteen months ago on my main system and they sounded very bad compared to the CDP.
I use the soundblaster cards in the office now, hooked into bose multimedias. They are definitely ok at that level.
To answer Sean's question. I use the Nodost moonglow spdif now, to a Lexicon mc-1b for the upsampling, to a pair of Martin Logan clsIIz and the sound is "very amazingly good". I also had the computer damped for noise around the disks and dynamat on the Qwin500 case and added software for the fans etc. Very quiet computer set on some aurios and using a pyton V2.
I would have to ask my computer helper if you wanted more info about the computer than that. I listen through winamp to great effect and have over 1000 favorite songs all in .wav format on a disk. They are from 40-90 meg a song.