Just to add my comments to the message about headsets, I find that Plantronics makes some of the best headsets. One huge advantage is that there are a few models of Plantronics headsets (I think the .Audio 480 is one) which have 3.5mm jacks but they come with a USB adapter so you can use them easily either as a standard analogue headset straight through the soundcard as well as as a stand-alone USB headset in which case your computer will recognize it as a separate audio device called "Plantronics Headset".
Good luck, Sieghard
