Leo, it does rather worry me that you couldn't hear any difference between the Audigy 2 and the X-Fi. The X-Fi uses some higher quality components than the Audigy and also no longer forcibly resamples all output to 48KHz using a really bad resampling algorithm (as the Audigy 2 did); the difference should be apparent on any reasonable equipment.
For your survey, I use a Turtle Beach Audio Advantage USB sound adapter as an optical transport to a Firestone Audio Spitfire DAC - http://www.firestone-audio.com/cgi-bin/product.asp?pdtseqnm=4 - which outputs to a Firestone Audio Cute Beyond dedicated headphone amplifier - http://www.firestone-audio.com/cgi-bin/product.asp?pdtseqnm=1 - which finally outputs to a pair of Grado Labs HF-1 headphones (no website since it was a special limited edition, but quite similar to http://www.gradolabs.com/product_pages/sr225.htm ). I don't think this is *completely* representative of the average Reg reader, though. :)
You might have done well in your review to focus more on the Dolby Digital Live feature of the card you mentioned. This sounds like it has the ability to convert non-standard multi-channel audio - which normally boils down to games - to Dolby Digital or DTS on the fly. This is a feature that is highly sought after by the audio enthusiast / gaming crossover market, as it's nice to be able to connect your PC to your high-end home theater receiver via a digital link and get surround sound from movies and games. With most cards you end up having both a set of analog cables to get the surround sound from games and also a digital link to get surround sound from movies (which is inevitably in DTS or Dolby Digital), and that's not very convenient or elegant. There's still no Creative cards that have this feature AFAIK.