Smholl,
Some things to consider:
1) The SB Duet is limited to 24/48 natively (bit depth and sample rate).
2) The Transporter will support up to 24/96 natively.
High-rez PCM files are an exciting option for digital users (allowing for more information).
You can also go directly from your computer to a USB DAC and experience true 24/96 capabilities (I recommend that you check out Wavelength Audio's USB DACs
here )
You can also build a server (with a streaming device like the Duet/Transporter) but I would look for devices that will support at least 24/96 natively). Personally, I am going with the new PS Audio Perfect Wave DAC (PWD) because it will support up to 24/192 natively and it will also function as a server (once their forthcoming Bridge device becomes available).
I recommend going
here to learn more about computer audio. Read up on the forums and dont be afraid to post questions.
Good luck.