Glass cannons, or their granite counterparts.

[marbleheadmaui]

I REALLY think Hearns having a bad chin is a myth. It just wasn't as good as his other gifts.

The top of the Glass Cannon list has got to be Bombadier Bob Satterfield, the 175 and heavy of the 1950's. He could take ANYONE out, but the top guys always got him first.
Florentino Fernandez was a kill or be killed guy at middle in the 1960's.
Tami Mauriello was one of these. Check out his incredible one round fight with Joe Louis!
George KO Chaney was a kill or be killed feather. HUGE puncher. Got drilled early several times.

Granite Counterparts

Vito Antuofuermo is an obvious one. He hit like a lightweight and took shots like a 175.
How about Clutchin' Sammy Angott?
Mike Quarry coulnd't punch to save his life. But I don't know that he took a ton of shots.

More recently Juan Diaz kind of falls into that category doesn't he?