Andrew,
I was having a similar problem....
I was just using the onboard sound on my ASUS A7V333 motherboard (with the Via KT333 chipset), using the fairly nice 6-channel CM8738 chipset for sound.
Well it did sound pretty nice, but, I couldn't even get the sound to run on all four speakers on my system in Linux, and when I couldn't get it to record sound for RogerWilco (a gaming colaboration app in Windows), I decided to install my good old, trusty SB Live card that I had moved to another system.
Ha-Ha, what an adventure. In Windows 98, the act of uninstalling the old sound drivers and installing the SB drivers made windows unable to boot in normal mode. Since I'm triple booting win98,XP and Linux, this wasn't a great concern.
But I was preturbed at not being able to have sound working in Linux. In, addition to listening to music quite a bit, I like playing Quake in Linux, and I recently got a hold of UT. So I definitely wanted to get it resolved (Did I mention I'm a gamer?
).
Well, I had been pulling my hair out looking at the modules and trying to figure out why I wasn't getting sound from an apparently already loaded module. Well, I really should have thought of editing /etc/modules.conf before, but, well, your post set me back on track, my friend. So thanks for posting the solution you found for your problem...
It seems a lot of people don't do that when they get a solution, and if somebody else has the same problem, they won't benefit from your experience.
P.S. In addition, now I have all four speakers working in Linux, and the sound quality is at least as good as in Windows.