You completely forget about Julian Jackson... The Work Jackson did at 160 was more brutal... at 160 I rate it #1 Julian Jackson, #2 Gerald McClellan
I think it's Bob Fitzsimmons.He cleanly knocked out a string of much bigger men and to concede 20 pounds to Corbett and knock him out with a body shot after 14 hard rounds was remarkable.
I would say Fitzsimmons or Langford but IMO they reached their truly impressive destructive capabilities when they started weighing in around the SMW limit. As far as career middles go? Ketchel.
Im surprised a lot of people is not saying Hagler..... But i agree. Bob Fitzsimmons is my choice as well.
All time - the fighter who has the most power in one punch, Its Julian Jackson... all these guys saying Fitzsimmons , Ketchel or Greb are just being nostalgic ... none of them can even come close to the one punch power of Jackson, and that's simply a fact.