On the Duran/Leonard thing, I'd offer this by way of explanation... Leonard was a smart, smart fighter. He had all the answers for Duran and Roberto couldn't come up with answers for Leonard. Add to this, Duran's heated, passionate, and intense! personality, a style that was dependent upon will, upon being able to take an opponent's soul, and an implosion is imminent. I believe, that on that night, Duran was a victim of self-combustion.
I gotta look at Baer again, but agreed on the other three, Pete. Aren't you a Marciano guy? I love Rocky's compact right hand. Beautiful, and deadly.
Yep, I'm a Marciano guy. Marciano had a terrific right hand. One of the best of all time. In terms of technique or speed Baer isn't at a world class level. However, Baer has arguably the hardest hitting overhand right in Heavyweight History. He killed a man with it and demolished Carnera with it. It's better than Ingo's in my opinion. Rocky's big right hand against Walcott was an absolute beauty. Very Compact, short, and very devastating. Mine isn't in order, either by the way. I also think Sonny Liston's overhand right might deserve a mention. I considered listing it.
I think Arguello throws the best right hand. Its textbook his right hand every boxer should copy Alexis for that. He is my choice but i could see someone saying like Hearns who had a great right hand and it was refined but not quite as perfect as Arguellos (for me anyway)