Here's how I want to set up my 5.1 receiver when I get it:
SPDIF coming from my PC in 2.0, and then use the receiver's bass controls and subwoofer pre-out to manage the sub. Is this a common ability of 5.1 receivers? I think my sound card can output in 2.1 but I haven't installed the software yet to make sure. If not, can a receiver typically take a 2.0 digital signal and send the subwoofer frequencies to the .1 channel output?