Ali asked that I encapsulate the Ring.com Best Ever by letter so it can become a permanent feature.
The list was compiled by Michael Rosenthal with limited input from Bert Sugar. The criteria included accomplishments in the ring with a heavy emphasis on strength of opposition as well as impact on the sport and thrills provided. The honorable mentions are in parenthesis.
A-Henry Armstrong (Alexis Arguello, Muhammad Ali, Lou Ambers, Sammy Angott and Abe Attell)
B-Charley Burley (Marco Antonio Barerra, Carmen Basilio, Wilfredo Benitez, Jackie "Kid" Berg and Jack Britton)
C-Ezzard Charles (Tony Canzoneri, Cassius Clay, Marcel Cerdan, Julio Cesar Chavez and Billy Conn)
D-Roberto Duran (Jack Dempsey, Jack Dillon, George Dixon, Jim Driscoll and Johnny Dundee)
E-Flash Elorde (Hiroyuki Ebihara, Frank Erne, Sixto Escobar, Cronelius Boza-Edwards and Antonio Esparragoza)
F
-George Foreman (Bob Fitzsimmons, Jackie Fields, James Figg, Bob Foster and Joe Frazier
G-Harry Greb (Mike and Tommy Gibbons, Joe Gans, Kid Gavilan and Emil Griffith)
H-Marvelous Marvin Hagler (Fighting Harada, Evander Holyfield, Larry Holmes, Tommy Hearns and Bernard Hopkins)
I-Ike Ibeabuchi (Luis Ibarra, Hiroki Ioaka, Guts Ishimatsu and Johnny Indrisano)
J-Jack Johnson (Eder Jofre, Jim Jeffries, Lew Jenkins, Beau Jack and Roy Jones jr.)
K-Stanley Ketchell (Peter Kane, Louis Kid Kaplan, Johnny Kilbane, Frank Klaus and Pone Kingpetch)
L-Joe Louis (Jake LaMotta, Benny Leonard, Ray Leonard, Ted Kid Lewis and Sam Langford)
M-Archie Moore (Rocky Marciano, Floyd Mayweather Jr, Terry McGovern, Jimmy McLarnin and Carlos Monzon)
N-Jose Napoles (Azumah Neslon, Kid Norfolk, Battling Nelson, Kenny Norton and Terry Norris)
O-Ruben Olivares (Manuel Ortiz, Carlos ortiz, Philadelphia Jack O'Brien and Carl "Bobo" Olson)
P-Willie Pep (Manny Pacquiao, Aaron Pryor, Billy Petrolle, Pascual perez and Eusabio Pedroza)
Q-Dwight Muhammad Qawi (Ike Quartey, Jerry and Mike Quarry, Robert Quiroga and Vincenzo Quero)
R-Ray Robinson (Barney Ross, Luis Manuel Rodriguez, Maxie Rosenbloom, Tommy Ryan and Jose Luis Ramirez)
S-Sandy Saddler (Salvador Sanchez, Michael Spinks, John L. Sullivan, Max Schmeling and Freddie Steele)
T-Gene Tunney (Dick Tiger, Bud Taylor, Lew Tendler, Felix Trinidad and Mike Tyson)
U-Paolino Uzcundun (Franco Udella, Yasutsune Uehara, Juan Urango, Alfredo Urbina and Jose Manuel Urtain)
V-Pancho Villa (Rodrigo Valdez, Fernando Vargas, Israel Vasquez, Wilfredo Vasquez and Benny Valger)
W-Mickey Walker (Jimmy Wilde, Barbados Joe Walcott, Pernell Whittaker, Freddie Welsh and Ike Williams)
X-Alfredo Xeque (why bother)
Y-Teddy Yarosz (Myung Woo Yuh, Jimmy Young, Hiroshi Yoshino, Yasuei Yakushiji and Don Kyun Kim)
Z-Tony Zale (Carlos Zarate, Fritzie Zivic, Daniel Zaragoza, Hilario Zapata and Juan Zurita)
Here is a link to the Z article which has all the writeups carried within it.
http://www.ringtv.com/blog/2303/the_best_of_all_time_a_to_z_zale/