the sound on the audigy is Better than my AC 97 sound on my 5680, I play games so the Creative was my solution. Can the card be used with Headphones, YES, there is a plug in for it and Creative supplies the headset too. if you already have a decent headset use those! as for the volume, the same buttons you use to crank up the volume (Again on the 5680) will work fine.
My main game of play is UT2K4, sound is important there.
Hope this helps.