ok...I think I'm getting close to figuring out what I'm going to do. I've got a line on an older 5.1 reciever that has digital inputs. I think I've decided on a set of speakers, so all I need is an audio card that has a digital out that I can hook into the receiver, no?

What I don't understand is these audio cards S-PDIF Output. What the heck is that, and how does that connect to a receiver?