the 70s-80s had so many great fighters who fought each other in their primes - we have some good fighters out there even today but get Mayweather-Paciquao about 6 years after the sell-by date.
NFL: 1975-85 - all the games were played in stadiums that were old dumpster fires, but goddman they were loud.
NBA: I would argue for today over the mid 80s. Talent is off the charts - however 3pt shots are getting a bit too easy when centers shoot them at a percentage that Larry Bird used to.
Baseball: 1970s - drugs almost killed the NBA in the same era but goddamn they made baseball goofy and fun
College Football: never really had a golden era, its always been quite fantastic, but all the games are on TV these days, so today?
Hockey: late 70s-early 90s - then scoring stopped because goalies got good and can wear fat suits