After listening to an X-Fi sound card for the last weekend at Quakecon, I can finally give some validation to the X-Fi sound card.
Being an audiophile type I took my HD-580's into the booth and listened to their demos on the X-Fi using my own headphones rather than the HD280 Pros they had there.
It is IMHO that this sound card is excellent and easily better than any onboard sound currently available. That includes the Via Vinyl 7.1 and the Creative 24-bit on the Neo4 SLI Platinum.
The new version of CMSS is excellent and for headphone specific users this is the killer feature of the new card. They say it offloads the sound onto the card specifically because it has its on processor and memory, but that doesn't seem to matter much on a newer system. The biggest advantage of the new X-Fi was specifically for headphone use. A few people left quakecon with these. I just don't think the spatial differences created by the X-Fi will be as spectacular in 5.1 or 7.1 as it is with headphones. If it is, it will only be on the highest end systems. There will be very little difference when using computer speakers in 5.1 to include the logitechs, the Rocket Tykes, the Klipsch in any form. The only difference will be the better transitional sounds from speaker to speaker. This is much better with the X-fi as compared to the Audigy 2 ZS, but it isn't as ground breaking as their new headphone technology.
Now don't get me wrong. This sound card was better than the HDA mystique, the Revo 7.1, the audiotrak prodigy and the like "IN GAMING", but it wasn't as much of a leap in 5.1/7.1 as it was in headphone use. If you are a gamer that uses headphones often or attend lots of lan parties, this is a sick sound card for your next setup.