Here are some of my favourites (in no particular ranking, and without reference to historical period):
Dramas/dramedies:
*The Sopranos
*Friday Night Lights
*Shameless (U.S. version)
*Wolf Hall
*House of Cards (U.K. version)
*Prime Suspect (U.K. version, with Dame Helen Mirren)
*Six Feet Under
*Dead Again
*The Borgias
*"Masterpiece Theatre" - whatever the hell they've got going ;-)
Comedies:
*Northern Exposure
*Newhart
*All in the Family
*Get Smart
*Carol Burnett
*Monty Python's Flying Circus
Talk shows:
*Johnny Carson
*Dick Cavett
*George Stroumboulopoulos
*Charlie Rose (I watch Charlie religiously, every night: it helps me in my work.)
(Sorry to Jon, and all Brits - there are obviously lots of great chat-shows in the U.K., but we only ever see isolated episodes, over here.)
Documentary Programmes:
*The Fifth Estate (CBC - I've been watching this since I was 10)
*Frontline (PBS - never miss an episode, of this show, if I can help it)
*The Passionate Eye (CBC, but features many British and American docs, also)
*The Independent Lens (PBS, and CBC)
"A" XOXOXOXOXOXO