The Bob Newhart Show is my all-time favorite from the 70's era. I, too, am watching the last two seasons and found the show REALLY stepped up with the laughs in the fifth season. Bob seemed to take a cynical, but hysterical turn and Howard got dumber and way funnier by year five.
Howard: What are you doing?
Bob: Bowling.
Howard: No, you're not!
Bob: I'm making a sandwich, Howard.
Howard: That sure looks good, I would go to my apartment and make one, but I'm all out of mayonnaise, and uh, bread, and meat.
Bob: What do you have in your refrigerator, Howard?
Howard: Frost.
Bob: Want half of my sandwich?
Howard: Oh, thanks, Bob, it saves me from eating frost. Uh-uh, your half is bigger than my half. (they trade) No, I was wrong. (they trade again!) There's a thumb print in this half.
Bob: EAT AROUND IT!
Rhoda
Mary Tyler Moore
All in the Family
Three's Company
Newhart
St. Elsewhere
Family Ties
Night Court
The Cosby Show
The Golden Girls
Perfect Strangers (I still think at times, it's very funny.)
Empty Nest