Media Center has certainly breathed life into my plain TV card using digital terrestrial. I have googled and found many command line switches, but none that makes Media Center start in live TV mode right away, rather than having me navigate the menu every time to start viewing TV, which is all I do with Media Center. Maybe someone here knows? In case there's any way to disable parts of Media Center I'd be interested to know about that too, just because it has so much else in it that I won't ever use.
Vista's Media Center: Command Line Parameters These Command Line Switches launches Windows Media Center and cause it to navigate directly to one of the built-in experiences: %SystemRoot%\ehome\ehshell.exe /directmedia:discplayback - Begins playback of the disc in the drive %SystemRoot%\ehome\ehshell.exe /homepage:VideoFullscreen.xml /PushStartPage:True - Live TV %SystemRoot%\ehome\ehshell.exe /homepage:VideoGuide.xml /PushStartPage:True - TV Guide %SystemRoot%\ehome\ehshell.exe /homepage:RecordedTV.BrowsePage.xml /PushStartPage:True - Recorded TV %SystemRoot%\ehome\ehshell.exe /homepage:VideoToBeRecorded.xml /PushStartPage:True - Scheduled Recordings %SystemRoot%\ehome\ehshell.exe /homepage:Radio.BrowsePage.xml /PushStartPage:True - Radio %SystemRoot%\ehome\ehshell.exe /homepage:Radio.xml - FM Radio %SystemRoot%\ehome\ehshell.exe /homepage:MusicBrowsePage.xml /PushStartPage:True - Music Library %SystemRoot%\ehome\ehshell.exe /homepage:VideosBrowsePage.xml /PushStartPage:True - Video Library %SystemRoot%\ehome\ehshell.exe /homepagehotosBrowsePage.xml /PushStartPage:True - Picture Library %SystemRoot%\ehome\ehshell.exe /homepage:Options.Home.xml /PushStartPage:True - Settings Menu