This is a little overdue but I did want to fully test the card out before posting.
Creative XtreameMusic x-fi sound card $129.00 USD. (Big thanks to Bubba for getting me this card as it is not available in Canada yet.)
Speakers used are Klipsch Ultra 5.1
Installation was a snap, deleted the old Audigy 2 value first and ran driver cleaner before installing the new card. First thing I noticed was a richer more fuller sound than the Audigy 2. Natural sounding would be a good way to describe it. After testing out the x-fi splash animation I proceeded to run some WMV HD vids. No hiccups, sound is good and rear surrounds are working nicely. The card comes with a DVD-audio player which is nice, playing a DVD-audio disc(Eagles Hotel California) was a real treat defiantly the best sound I have ever heard out of computer. Obviously not as good as a proper home theater system but pretty darn good. The card also comes with a nice software suite which includes a speaker tester. Helpful for making sure your left right and center are connected properly.
On to
BF2, as you may or may not know
BF2 directly supports the x-fi card at the hardware level. Selecting x-fi in the audio setting allows you to move the audio quality to ultra high. Note I am comparing to an Audigy 2 which supported EAX. Was there a huge difference..in short no. All of the EAX effects work well, ie drive a jeep into the tunnel under the Kubra dam and you'll get an awesome echo effect. The Audigy 2 did this as well, I would say the x-fi card was a little more pronounced with the effects, but there are no new or additional effects added that I have noticed. If you are using onboard audio without EAX I would recommend upgrading to the x-fi. Battlefield sounds amazing in 5.1, the games audio is very directional, ie if a chopper is approaching from behind you'll hear it behind you. The sound will move forward and right over you as the chopper passes. I would say if you already have a EAX supported card you won't see a dramatic improvement. Overall I am very happy with the card and have had no technical problems to report as of yet.