Squeezebox, USB to S/PDIF conv, or soundcard?

I currently have a Squeezebox in my main system and I'm thinking of connecting my computer to a second system so I can utilize my music db on that system also. The system is located in the same room as the computer so I have a few options on how to do this and I'd like to get 'goners opinions on which route will be the best way for me to go. I already have a DAC so my choices are:

1.) Get another Squeezebox (most likely connected via ethernet rather than wireless). I'd probably go with the Duet and put that in my main system and move the SB3 to the computer room.
2.) Get a USB to S/PDIF converter and hook that to the DAC
3.) Get a soundcard with S/PDIF out and hook that to the DAC. I run Linux so the soundcard would have to be Linux compatible.

I don't need anything really high-zoot as this is my second system and it's in a relatively noisy environment since it's a few feet away from my computer. However, while I find it fairly easy to tune out the fan noise from the computer, noise mixed in with the music is another story. My second system consists of a Bryston .5B preamp, Pioneer DV-626D DVD player, Bel Canto DAC1.1, Forte Model 4 amp, and Paradigm Reference Studio 20 speakers if that helps. Certainly nothing great by any means but it's just my second system so I can't be too picky. Any opinions on which route I should go to hook my computer up to this system are greatly appreciated.

TIA,

Spike01