asterisk users - Nov 2004 - Headsets for Polycom Soundpoint 500/600

What headsets have people found work well with the Polycom Soundpoint 
500 & 600?  If any of the headsets that work with the Polycom's also 
work the Cisco, that would be an added bonus, but is by no means a 
requirement.  I am not looking for a headset that requires an external 
amplifier, but rather a headset that can make use of the headset jack on 
the phone itself.