Yeah, definitely Monzon, I think nobody would dispute that..... The second place is a lot harder to tell, it´s between Locche, Perez and Galindez......
Julio Cesar Vasquez is a top-10 guy. He was really, really good for a handful of years. And some guy named Martinez is doing alright. But Monzon is an ATG.
Santos Laciar and Horacio Accavallo are often overlooked. But I think you'd have to say Monzon and Pascual Perez are numbers 1 and 2.
Perez and Accavallo are arguably greater than Locche. Monzon, Perez, Locche, Accavallo, Galindez would probably be my top five (off the top of my head) BUT I would happily sub' Galindez for Lacier, one of my favourites and as Surf-Bat has said above, painfully underrated and rarely given his due.
Maybe not the greatest Argentinian, but one of my favourite fighters was the left hooking middleweight of a tough MW era, Eduardo Lausse...H2h he whips Martinez...
thats what i first thought but im not so sure now, i dont really know, i know he had weak skin above the eyes, (loss to cervantes.)