I used to have a Terretec DMX6 fire built in PCI soundcard and breakout box which fitted in a 5.25 bay on the front of the PC. It was superb, but is not supported in Vista 64bit, so I am really upset by that.
It had mic and headphone jack and had a built in headphone and mic amp. Each had volume controls. could you look for a USB or PCI soundcard which has built in mic and headphone amps?
Terratec make a USB version of their card which works with Vista 64 bit, but is expensive. May be someone else in this community can suggest a cheaper alternative.