The RTM version of WS 2008 dropped on Saturday. Let the games begin!
I was talking John Fontana (Senior Editor at NetworkWorld) yesterday, and he mentioned a report of a misleading message when doing an in-place upgrade from WS2003 to WS2008. If there are any third party apps installed on the server being in-place upgraded, a dialog appears that says something to the effect that the third-party apps are not supported. The intent of the dialog box is to inform the administrator that the 3rd-party apps might not handle the in-place upgrade properly, but some people have interpreted it to mean that the 3rd-party apps are simply not supported at all on WS08, even when they are. I don't have the exact text of the dialog, but apparently it is pretty confusing. Be prepared for support calls.