I used to follow the Rightmark audio forum closely. These audio experts measure soundcard performance objectively.

http://audio.rightmark.org/
Speaking of soundcards, another alternative is to get a high quality external DAC accepting USB or FW input (or maybe even truly optical input for complete electrical separation between the noisy PC hardware and your audio system; which will of course require a an optical card of some sort. SPDIF & Toslink is more conventional.
Of course if you want to just jack a headset into the PC then you probably want a PC soundcard - or maybe something like this?
http://www.audiophileproducts.com/fubar3
I don't own this and haven't reviewed it - but it shows a simple USB DAC - it's space efficient, uses asynchronous data buffering (USB protocol rather than streaming SPDIF with embedded clock signal and has a separate power supply, not drawing power from the same PSU as the PC).


No special audio drivers required - the default Windows USB audio wave device driver can be used, it's built in and more or less any version of Windows, certainly Vista and 7 will detect and use the soundcard. Rely on Microsofts driver, not some 3rd party mish mash.