What mobo you got in there? I'm running an Abit NF7-S v2.0, and using the optical out on that. Was planning to buy an Audigy 2 but never got round to it.
Dave
BTW, I would suggest moving the speakers further apart, I originally had mine like that, moved em further apart and the 5.1 audio on dvds etc sounded better. There was more of a distinction between left right and centre, so the Surrond Sound bit came more to life. Have you got it linked up with the Skybox? and Video/DVD player in the pic?