Hi Steven,
On our Campus we use all Plantronics headsets,but I'm sure you know that there are many many models out there to purchase.Here is a link for Plantronics so you can check out what they have to offer (check out the L510 and L510S or CS50 - USB).
http://www.plantronics.ca/canada/en_US/index.jhtml
Also,here is a link for Cisco tested headsets for IP Communicator.
http://www.cisco.com/pcgi-bin/ecoa/Search?KEYWORD=Communicator&KeywordSearch=1&isAffil=
Hope this helps!
Rob
Please remeber to rate helpful posts.....