I have been having issues with Vista running on the Toshiba M400. I installed the RTM bits last week. The Windows Mobile Device Center stopped working, I couldn't VPN in to my clients machines, various other features were misbehaving.
This morning I discovered (thanks to Nick Randolph) that all my issues are actually issues with the OneCare beta. 10 minutes later the OneCare beta was removed from the machine and everything is humming along nicely.
If you are working on the OneCare team (or know someone who is) "come on, sort it out!".