Darkine: Where did you get that rumor from? Chris Priestly from Bioware officially stated on their forums that the game will run in XP and Vista:
Mass Effect Community - Mass Effect for PC System Specs, SecuROM and FAQ
And yeah, onboard sound does the trick for me too...never bothered with expansion sound cards.
IRML: Yeah, I've heard of it, but I haven't really given it much thought...when I finish the current games I'll see about maybe getting it.