<< if you already have a SB Live! that actually works (few do) >>
Man, that's pretty harsh. So you are arguing that SBLive's have a failure rate of 60-70-80%? That's ludicrous.
By all means, any potential buyers of the Audigy should educate themselves on its features, but its 24-bit processing, high-definition EAX, improved compatibility, "industry standard" status that game makers produce and test for, etc., make it certainly one of the top soundcards on the market today.
Btw, if you've got the PCI slots, you can have more than one soundcard installed. (You can switch between them in the "Multimedia" tab of Control Panel.) If you are worried about compatibility, you might want to have more than one soundcard installed. The MX300 (aka Aureal Vortex 2) card still has the best headphone sound of any soundcard, and it is definitely the best for Counterstrike and other Half-Life variants, so you might want to keep it simultaneously installed, armando.