Some people with m/b's with VIA chipsets have had problems - popping and crackling sounds in particular - when it comes to the Audigy. As have people with Intel/SIS/AMD/etc motherboards. And yes the Audigy card does use 3 IRQ's, but you can get away with sharing them unless you experience problems.
The Audigy is technically a good card, but because of these issues, it isn't a favorite with many people in the technical world (I wouldn't go as far as to say what the above statement says RE "child molester" though!).
The Turtle Beach Santa Cruz and the Hercules GTXP are both very good cards which offer better value-for-money. The technology used in both of these cards also produces better virtual 5.1 sound on 2 speaker systems, and better bass on cheaper speakers.
Having said that though, I have an Audigy. I'm happy with it running through my Sony SAVA-7's and Yamaha TSS-1 speakers. I've never had any problems with it and I've (hopefully) invested in the future with something that supports EAX Advanced HD.
What you choose is your choice. But if you were to buy the Audigy, I'd try to buy it from a place where you can return it if you do experience problems.