Seinfeld for its social reflection, relevance and irreverence. The Golden Girls for a quartet of great actresses showing us that fun, love, and sex never get old. Maude because Bea Arthur is a lost treasure. Arrested Development for its quirkiness and for re-introducing us to Jason Bateman. Are You Being Served? for being ridiculously camp and frothing with double entendre. Frasier because I didn't appreciate it the first time around and because Niles and Frasier are the gayest straight men around. The Simpsons in the mid 1990s because it had more bite. That was before they discovered that it was just easier to write Homer as an absolute idiot. Diff'rent Strokes just for the nostalgia of it...that sh1t cracked me up as a kid.
Cool topic, though someone posted "The X Files" as their favorite sitcom earlier -- LOL.
The Jeffersons The Golden Girls Spin City (when Michael J. Fox was on it only) Roseanne The Simpsons (still going strong and I love both classic & new episodes!) Married ... With Children Friends Third Rock from the Sun Family Ties Three's Company
No one has mentioned The Bob Newhart Show yet? The 90's Newhart was pretty good too. But the original one was a classic.
The Cosby Show hasn't been mentioned yet either?
I'm happy to see someone mentioned Mary Hartman Mary Hartman, a spin off of Fernwood Tonight.
Others that deserve mention but may be obscure: The Gary Shandling Show (not to be confused with the Larry Sanders Show which is not old yet). Anything But Love (Richard Lewis and Jamie Lee Curtis) Dream On