Livre d'Or

USB headset is what you want. Amazon reviews will give you a good idea of how well an individual one works. I'm currently using one from Logitech (can't seem to find the model number, but it's old enough that they probably moved on). Plantronics is also generally good. Look for something that will be comfortable for the way you wear a headset and that has a noise-canceling mic.

But the trick is to get a direct USB connection. The less the signal has to be converted and processed, the better off you'll be. A USB headset will bypass your sound card, taking one step out of the process. But if you get a USB adapter, that sort of defeats the purpose.