Northern Exposure
ER
NYPD Blue
House
Married With Children (sorry, I find it hilarious)
Lost
Dirty Jobs
Mad Men
Carnivale
Star Trek (original, and why is it never on one of the billion cable channels, on a weekend afternoon?)
Hill Street Blues
Babylon 5
Buffy the Vampire Slayer
Doctor Who
The Dick Van Dyck Show
Arrested Development
Coupling (UK version, of course)
Pushing Daisies
The Simpsons
Picket Fences
Others I thought of are Cosmos, The Day The Universe Changed, Nova, American Experience, and numerous others shown on The Science Channel, Discovery, and The History Channel (THC, with the caveat that their inaccuracies bug the hell out of me).
Mystery Science Theater 3000 (Especially the Joel years)
Simpsons
Star Trek
Star Trek TNG
Wallace and Ladmo (local kid show, off the air after decades)