In my time, probably the biggest fight of all time, that was talked about and never made was Jones vs Tyson, and in more recent years Mayweather vs Pacquiao. But, what's always a surprise to me is that Archie Moore was supposed to get a third crack at the heavyweight title--- a little known fact that is seldom talked about.
Everybody knows he defeated the likes of Mike DeJohn, Nino Valdes, and Bob Baker to get his shot at Rocky Marciano. And everyone also knows he was in the mix, after the Rock retired, in a failed bid to win the vacant crown against Floyd Patterson. After Patterson, however, he won fights against Charley Norkus, Howard King, and Willie Besmanoff--- keeping him in the top ten contenders mix. He also defended the LHW title during this time.
The result was, he was given a contract to face newly crowned champion Ingemar Johansson, as this picture shows:
Moore, at the time, was taking to an acting career playing the runaway slave Jim in the Adventures of Huckleberry Finn; but already had the contract to face 'Ingo' the following year (1960). This, of course, never happened. Johansson would lose to Patterson, and also lose the rubber match--- and Moore was stuck in pugilistic limbo competing in professional wrestling events either as a referee or opponent. The last big fights of his career came in 1962, when he lost to a newcomer named Cassius Clay--- a young man he attempted to train some time before--- and Giuilio Rinaldi in 1961 in what would be his last defense as LHW champion.
Considering Johansson's meteoric rise and fall, and the fact that Moore would soon burn out as well--- its interesting to wonder, had this fight taken place--- who would of won the contest. Most would assume the younger, faster, Johansson would win--- but Moore was still kicking ass and taking names against reasonably well contenders.