All time
Heavyweight: Ali
Cruiserweight: Holyfield
Light Heavyweight: RJJ
Super Middleweight: Benn
Middleweight: SRR
Light Middleweight: McCallum
Welterweight: ODLH
Light Welterweight: JCC
Lightweight: Duran
Super Featherweight: Arguello
Feathwerweight: Morales
Super Bantamweight: 'Bazooka' Gomez
Bantamweight: 'Puas' Olivares
Super Flyweight: tied between 'Pikin' Quiroga & Gilberto Roman
Flyweight: 'El Maestro' Canto
Light Flyweight: 'La Chiquita' Gonzalez
Minimumweight: 'Finito' Lopez

Current/Active
Heavyweight: Wladdy
Cruiserweight: Haye (I know he fighting Heavy. soon)
Light Heavyweight: 'Bad' Chad
Super Middleweight: tied between Kessler & Andrade
Middleweight: Abraham (Amin Asikainen is slowly becoming my fav. since I think Abraham is very beatable and will loose soon)
Light Middleweight: ODLH
Welterweight: Cotto
Light Welterweight: D-Hop
Lightweight: Katsidis
Super Featherweight: Alex Arthur
Feathwerweight: JMM
Super Bantamweight: De Leon
Bantamweight: R. Marquez
Super Flyweight: Arce
Flyweight: Pongsaklek 'La Arana' Vasquez
Light Flyweight: 'El Increible' Cazares
Minimumweight: Well it was 'Iron Boy' Calderon but hes fallen off IMO, so now it's Eagle Kyowa.