The Cisco VPN Client for Vista works great unless you want to run the 64bit versions.  I installed Vista Enterprise 64bit with Service Pack 1 onto my Thinkpad T61p recently.  This install went very easily and I was pleasantly surprised to find that Lenova had 64bit versions for all their software.  I then went to look for a 64bit version of the Cisco VPN client and was surprised that they haven’t announced support for, nor published a beta for the Legacy client.  They have a SSL VPN (AnyConnect?) version for 64bit but not the legacy client.  This is surprising.  Attached is a MS link for more information: http://support.microsoft.com/kb/929490