EAX is okay ... as long as it's not on a Creative card.
For years, I bought any card I could get a hold of with an Aureal chipset. When Aureal folded and support went down the tubes, I broke down and went Creative, until I realised their cards went through a quality control scheme that involved three-year-olds with multimeters and trained monkeys screaming at Pat Boone records. They're also not very kind under the NT kernal, although the Audigy seems a bit more graceful under XP (maybe the "soon-to-be-released" new Live! drivers will help, but I wouldn't hold my breath). Still, you can get a lot better cards than the Audigy for a lot less, and many non-Creative cards offer both EAX and A3d support (although if you really want EAX3, you'll still have to buy an Audigy).
I guess the one advantage the Audigy has is 24-bit ASIO support, but if you want a budget studio you'd still be better served by getting a dedicated recording card for the same price.