Strangers with Candy (1999-2000) *
Doctor Who (1963-present)
Mystery Science Theater 3000 (1989-1999)
Pee-Wee's Playhouse (1986-1991)
Twilight Zone (1959-1964)
The Simpsons (1989-present)
The X-Files (1993-2002)
These are all excellent. I watch them whenever they come on TV (Unfortunately, some of them don't anymore.
). Haven't watched all the episodes, but I'll probably rent all of the shows on DVD one day and watch them.
Freaks and Geeks (1999-2000)
Battlestar Galactica (2003-present) *
Never liked Freaks and Geeks too much. It was an ok show, but nothing close to the list above. I was never able to get into Battlestar Galactica, although most people seem to rave about it.
The Avengers (1966-1969)
I've never even seen this, but I know about it. I originally thought it was about the Marvel Avengers. No such luck.