PC Surround sound question

[Silvio Manuel]

I currently have a modestly-spec'd out PC (Athlon 3500+, 2GB RAM, 256MB Nvidia 6800 video card), but with a Soundblaster Audigy SE sound card. I bought a pretty professional-level sound card awhile back for music production (M-audio Audiophile 192), which does not directly support 5.1 surround sound. It does however, have this feature "digital I/O supports surround-encoded AC-3 and DTS pass-through "

I will soon be installing this sound card, but as I've gotten back into gaming recently, I would like to also enjoy 5.1 sound (or even 7.1 if it's not cost-prohibitive).

What would be the best way of doing this? Other than actually buying the speakers I need for a 5.1 set-up for my PC, should I...

- Buy a USB2.0 external sound card that supports 5.1? So in effect I would use my internal M-audio card for music, and the external USB2.0 5.1 card for games... if that's even possible?

- Instead of buying an external sound card, buy a (fairly cheap) 5.1 surround sound system that comes with a receiver, and run the "digital I/O DTS pass-through" from my M-Audio sound card into the 5.1 receiver for IT to decode the 5.1 signal to the speakers?

- Any other options?

Thanks!

-SM