Mystery Science Theater 3000 is a big one, although with Cinematic Titanic I've got something 99% as good. :)
The One, True Mission: Impossible is another biggie.
Star Trek, not so much ... given how wrong it's tended to be post-1980, I think it may be just as well to let Star Trek go.
However, the real biggie has got to be A&E's brilliant Nero Wolfe Mysteries with Timothy Hutton as Archie Goodwin and Maury Chaykin as Nero Wolfe. That was one seriously awesome show, murdered by an idiot incoming program director who cared more about his own ego than quality content.
Doctor Who is technically still around, of course, but I do miss it's older, more in-depth storytelling, as opposed to the contemporary "Cliff Notes" plots.