Honestly, I'm down with TV from all decades. I don't think the decade says it's good or bad TV. I think the concept, the showrunners, and writers (as well as actors) say it's good or bad TV.
I think that's really true. I can think of great TV shows from all eras that I really like. I mean c'mon, nothing's funnier than I Love Lucy! And yes, today there are more reality shows & crap like that, but we also have more options, including "free cable" that are making quality shows (F/X, USA, etc).
I do have to say that in general sit coms were funnier "back then" then now. When I think of all the sit coms I have loved (Lucy, M*A*S*H, Three's Company, Cheers, Seinfeld, Friends, Will & Grace, etc), I can't really think of any today that I like save for The Big Bang Theory (well, I do love Hot in Cleveland). I'm not even that big of a HIMYM friend except for NPH.
The '60's and below (Bet I'm the only one who votes for this one!) primarily because I was younger and more impressionable then. But the late '50's and early '60's had the shows that I am always the most nostalgic about.
T H E Cat
Gunsmoke
Sea Hunt
Wagon Train
Maverick
Have Gun, Will Travel
Superman (the first series, starring George Reeves)
Lawman
The Life And Legend Of Jim Bowie
Roy Rogers And Dale Evans
(and what list from that era could possibly be complete without the greatest series of them all? The one, the only, the greatest, the original.....)
STAR TREK!!!!!!!!!
Aack, Star Trek karma! The original is so cool. I can't believe you didn't mention Highlander (I know, not the same era). And don't forget the original Batman shows! I'm trying to find those on DVD or online for my youngest to watch.
I think a lot of us are choosing 90's and later (besides that's the era that most of us grew up in) because that's when tv started being taken seriously as an art form and really talented writers and actors started choosing tv over movies. I know that for me, I would much rather spend an hour watching an episode of Dexter, or some other tv show, than risk losing an hour and a half to see a movie at the theater.
These days, I have to say that is so true. We spent big bucks to go see Dylan Dog: Dead of Night and left halfway through. I think there is incredibly quality on TV, and I'd rather spend my time watching what I know is going to be good, rather than a new movie that I have no idea if I'm going to like.