I doubt with onboard you'll actually experience "wayy better" sound. But if you're paranoid about your sound as I am, then select kernel streaming, and resample to 48000Hz as your onboard probably does this internally. I don't know if your card will support 24bit sound, but you can try it. Oh...
Hell, I watch DTS ES 6.1 DVD's on my 2.1 speakers, just make sure your DVD software is set for as many channels as it supports, and let your card drivers downmix it to 4.1.
Oh and DTS > Dolby, it's a higher bitrate, and usually more well engineered, format
This http://www.ubernet.org/index.php?p=UberGuide is the best tutorial ever :) Though, if you do want to go lossless (flac), then only a few changes are needed to make with this tutorial
I heard the Revolution 5.1 actually had better DAC than the 7.1, I can see by the hardware specs that it does have a bit better SNR than the 7.1 (107dB vs. 109dB), but no one really mentions the 5.1. Does anyone know if the 5.1 would be a better buy in terms of sound quality than the 7.1?
Not counting drivers, or the OS, or all that, it's usually in this order:
Nod32 or AVG Free
Mozilla Firefox
Visual Styles (StyleXP)
Foobar2000 and needed components
ServU FTP
and much more including Nvidia DVD Decoder, Konfabulator, Trillian, etc..