By X-Fi do you mean something like this?
I'll get to work researching the DT770 and the ATMH50S then...which is good, because I need to take a break from researching international supply chains ><
Though on the upside, with the knowledge I gain I could help EK learn to stock keyboards faster than...never.
No, are you using a laptop? if so, this is your better bet:
http://www.amazon.com/Creative-Sound-Blaster-System-SB1240/dp/B004275EO4/ref=sr_1_4?s=electronics&ie=UTF8&qid=1297824303&sr=1-4If you have a desktop and have a PCI-Express X1 slot or better:
http://www.amazon.com/Creative-SB0886-Titanium-Fatal1ty-Professional/dp/B0018EFGTM/ref=sr_1_2?s=electronics&ie=UTF8&qid=1297824345&sr=1-2if you want the front bay (with headphone and mic ports and volume control) then this:
http://www.amazon.com/Express-Blaster-Titanium-Fatal1ty-Champion/dp/B001BDPLJA/ref=sr_1_1?ie=UTF8&s=electronics&qid=1297824379&sr=1-1There are many options, though no one particular option is the best for any given person.
I figure it this way, optical output from the X-Fi, with wasapi or with just plain old foobar output should perform as good as I'll ever hear. So I basically utilize my X-Fi as a transport. The only reason it's there over my onboard audio is that it handles spatial audio processing and offloads some of that load to my CPU, loads music faster, and does a few things better. Considering music and gaming are major parts of my life, it makes sense to meet in the middle somewhere...
For speakers, it goes:
X-Fi (stereo output) -> Klipsch Promedia 2.1
For headphones, it goes:
X-Fi (optical output) -> SD-793 Mini-DAC -> Little Dot I+ -> Whatever can I'm using.
I have "output stereo mix to optical" enabled so I can switch between the two without making any changes, and when gaming if I choose to use my headphones any and all output goes to both places, and by not using the optical as the default, I get all the features the X-Fi matters for. Also, when all I want is music, I can setup WASAPI in foobar and output to optical, so no other sound comes out, since windows default sound output is the stereo mix, it never makes it there since the optical output is locked down by WASAPI. Makes a good "kill switch" for everything else besides music, a lot of people argue there is some SQ improvements but I wouldn't dare start that argument here or anywhere else as I have no experience suggesting one way or the other.
Optical, ideally should give me the best possible sound quality if output to a good DAC. Arguably there is some merit to a better sound card, but realistically I won't ever spend enough in that card's lifetime for me to consider upgrading it. For now, it's as good as it'll get.
Basically, it's an EAX processor, a digital transport, a speaker output and many other things. It just does a lot of things well and based on my needs, it fits the bill perfectly.