I haven't reviewed all of the posts for a couple of weeks. I've been reviewing them today but don't yet see a straight answer as to anyone having gotten a Vista machine to reliably connect.
If someone has figured that out, please post the details of your working configuration here.
Here's where we stand on some Vista troubleshooting we've done lately. This does not fix the problem but does document some minor progress.
Like most everyone else, our XP clients have no problems connecting whatsoever. Our standard uses WPA2-Enterprise, AES, PEAP with MS-CHAPv2 and using the user's credentials as cached by the laptop. Our test Dell laptop Vista machine is using one of the newer Intel driver releases [v.220.127.116.11 (TIC148234) release date 11/19/2007].
We've found that with Vista, we not only had to remove the CCKM from our WLAN but we also had to disable several other settings within the TCP/IP settings of the laptop's Wireless NIC.
With CCKM enabled, debug on the WLC threw the following error: Tue Nov 27 12:13:08 2007: xx:xx:xx:xx:xx:xx Invalid EAPOL version (1) in EAPOL-key message from mobile xx:xx:xx:xx:xx:xx
Our laptop couldn't connect. Then we disabled IPv6, Link-Layer Topology Discovery Mapper and Link-Layer Topology Mapper. After disabling these settings we could get an IP address from the DHCP server. We had network connectivity for a few minutes but then we lost it. We found that Vista re-enables all of those settings within the Wireless NIC. We retain our DHCP assigned IP address but we can no longer ping the Default Gateway.
We don't have very many Vista users yet so finding a fix for this is not top priority. I will post more as we find time to keep debugging.