You didn't say whether you bought the X-Fi card "upgrade" because you:
A.) Now have an interest in gaming, or other capabilities offered by X-Fi.
B.) Just wanted to upgrade, looking for improvement over "old" card.
This makes a difference to me.
Scenario 1.) Creative's products are truly multi-media devices... surround output, EAX, etc... necessary? No, but if you want that for movies and gaming, then Creative is the best choice.
Therefore, you would at this point just add an external DAC. Then you can keep all the nice features, but improve on the sound quality.
For example, I have an Audigy and a AV-710. I decided to
add this because I would expect nice synergy with AT's
ATH-A900 cans.
There are *many* DAC options available to you. The Trends is an affordable and versatile example... but really, theres alot of choices so it depends on needs and budget.
Scenario 2.) You may wish to get into a card more geared for audio only. Like the one you upgraded from.
Before I did that, I'd be trying one of these. They seem well rounded but with the emphasis on music use.
Onkyo SE-200PCI HD PCI Digital Audio Board $199.00 USD
Onkyo SE-150PCI PC Digital Audio Board $179.00 USD
The above offer 7.1ch out, the below is straight 2ch.
Onkyo SE-90PCI PCI Digital Audio Board $129.00 USD