Unless I'm mistaken, Creative's sound cards won't be of much use in Vista, since it does everything in software now...
Many of the effects and extras Creative provided are done by Windows itself now, and they also got rid of DirectSound and DirectSound3D (no more hardware acceleration, and support for only stereo software mode as a fallback).
I would have been excited about this pre-vista, but now I'm not seeing the advantage of having a discrete graphics card if it's just going to be a better quality DAC with a better SnR...