Clearly, I'm not sure what genuinely meaningful things I have left to say about television history in the 1990s (Full House, baby! Those Seinfeld lads!), so I'm going to say what I will do going forward (once I finish the 1990 list). I will instead just do a top five for each decade moving backwards. Here's a visualization:
Top Ten Shows of the 1980s
Top Ten Shows of the 1970s
Top Five Shows of the 1950s and 1960s
Sound good? Neat. Asterisks abound for those ones, but hey, if you dominate a decade, you're probably a Hall of Famer all the same. Like Bill and Wilt!
Honorable Mention: The Fresh Prince of Bel-Air