Most of my users use HP laptops on the wireless driver version 188.8.131.52, which is supposed to be very stable. They are very stable when doing static WEP, but at work we're using WPA with TKIP, using the Microsoft wireless client. And when doing WPA, the stability is greatly decreased - users experience frequent changes in data rates and eventual drops. The connection gets re-established and the same thing happens all over again.
I've been seeing the same thing on Toshiba Protege WPA/TKIP/PEAP with the same driver version (Intel 2200BG). Performance and RSSI drops to -92db, even though laptops in the same office with Cisco 350 are showing -60db. I haven't been able to track it down yet. The clients are XP2 and the AP1200 are controlled via LWAPP/WLC 184.108.40.206.