Not only is Standby not possible since initial installation, now even Hibernate balks at my sincere request for cooperation:
Not that it worked great before - the last hibernation took almost three minutes for 1GB of memory. The XP installation on the same box still works fine... I have the sinking feeling I am in for more "surprises".
Application note: Forgot to mention that Daemon Tools wouldn't install, but that I almost expected.
Update Longhorn experiment terminated. It hung with not even Ctrl+Alt+Del reacting any more. Looks like something went awfully wrong with my installation.