1. Harry Greb
2. Henry Armstrong
3. Roberto Duran
4. Rocky Marciano
5. Jack Dempsey
Honorable mentions:
Mike Tyson
George Foreman
Joe Frazier
Manny Pacquiao
There were far too many to just pick five, please forgive the lengthy list.
Old School:
1. Jack Dempsey
2. Harry Greb
3. Jake LaMotta
4. Carmine Basilo
5. Archie Moore
6, Ike Williams
7. Bob Fitzsimmons
8. Stanley Ketchel
9. Sam Langford
10. Henry Armstrong
Modern era:
1. Roberto Duran
2. Julio Caesar Chavez
3. Marvin Hagler
4. Mike Tyson
5. David Tua
6. Tommy Morrison
7. Manny Pacquiao
8. Carlos Zarate
9. Joe Frazier
10. Edwin Rosario
Of the fighters that haven't been mentioned much here
Joe Frazier
Aaron Pryor
Edwin Valero
Sonny Liston
John Mugabi
Gerald McClellan
And Marvin Hagler was a savage when he fights aggressive
Fighting today:
Golovkin
Lucas Matthysse
Roman Gonzalez
James Kirkland
Alfredo Angullo
Kovalev
Magomed Abdusalamov
Jack Dempsey, Jeff Fenech, Stanley Ketchel, George Foreman and Rocky Marciano, though a good case could be made for Gerald McClellan.
Mike Tyson, Roberto Duran, Prince Naseem Hamed
I would say without a doubt that Jack Dempsey and Henry Armstrong belong on this list
