My personal top 15 is as follows:

1) Henry Armstrong: I know having Hank first will cause some controversy, and I completely understand why most have Robinson ranked first, but Hank's accomplishments were AMAZING. At a time when there were only 8 championships available he held 3 (Featherweight, Lightweight and Welterweight) simultaneously. He beat HOF competition during his run and was a fighting champion with an all action style. What separates Hank from the original Sugar Ray to me is that as great as Robinson was, he wasn't able to win that third title in his third weightclass. As stated previously though, I can see why most rank Ray 1st in these lists.
2) Ray Robinson: Fighting perfection. Amazing reflexes, heart, chin, one punch power, superb boxing ability, mental toughness, stamina and a desire to be recognized as the best by fighting and beating the best. I can see a strong case for Ray being number 1, but for historical accomplishments I prefer Hank's to Sugar Ray Robinson's, although I must admit that Ray beat better competition and was more dominant for longer (most likely due to Hank's all out style).
3) Muhammed Ali: In my opinion the greatest heavyweight ever who beat the best the division had to offer over 3 generations. Transcended boxing and is a historical figure recognized by all and looked up to by many of today's athletes. Beat HOF and ATG champs like Liston, Foreman, Frazier, Patterson and many others. Fought in the "Fight of the Century", Thrilla in Manila, and the upset in Zaire. Ruled over the greatest collection of heavyweights the planet and sport has EVER seen.
4) Roberto Duran: On the short list of candidates for greatest lightweight ever (with guys like Whitaker, Armstrong, Chavez and Benny Leonard, to name a few). Able to box or brawl and was brilliant on the inside and able to close the gap against the fastest of fighters. Great knockout puncher at 135 who could set a magnificent pace that other fighters could not match. Beat HOF fighters at 135, won multiple titles up to 160 (fight vs. Davey Moore and Barkley were phenomenal wins), gave the great Marvin Hagler all he could handle, but his main claim to fame and the reason I rank him so high is that he beat a prime Sugar Ray Leonard who is a fellow top 10 ATG. Laziness caused losses to Leonard in the rematch as well as a few fighters with less talent, and his blowout loss to Hearns place him no higher than 4 on my list.
5) Joe Louis: #2 Heavyweight ever, in my opinion, and another fighter who transcended the sport, breaking the color barrier and paving the way for guys like Ali, Tyson, Holyfield...etc. Didn't beat the level of competition that guys like Ali, Frazier, Holyfield or Lewis beat, but took part in arguably the most historically important fight in heavyweight history: his one round annihilation in his rematch vs. Max Schmeling during WWII. Set the record that still stands today by defending his title (the only one available at heavyweight at the time) a record 25 times. One of the most vicious punchers in the history of the sport, I place him behind Ali due to Ali's better competition and the fact that Joe was stopped by Schmelling while in his prime where Ali wasn't beaten until fellow ATG Frazier caught him just past Ali's prime (and that by close decision in a 15 round fight).
6) Sugar Ray Leonard: While his career wasn't as long or consistent as those ranked above, Ray fought and beat numerous HOF and ATG fighters during his illustrious career. Beat P4P, HOF fighters like Wilfred Benitez, Roberto Duran (ATG in rematch), Tommy Hearns (ATG) and Marvin Hagler (ATG) and held titles at multiple weights. While the Hagler victory was questionable (in my eyes), he came out of retirement to face the most feared champion and while I thought Hagler won, there is no doubt that Ray pushed him to his limit. Additionally, one only has to watch Ray's fight vs. Hearns to see what a truly special fighter he was. Look at my description of Robinson above and that is Leonard. He loses points for so many retirements and the fact that he lost to the smaller Roberto Duran during their primes.
7) Ezzard Charles: In my opinion Charles is the greatest 175 pounder in history and proved so by destroying top competition, to include stopping fellow prime ATG Archie Moore. Charles was never the same after killing one of his opponents in the ring, but went on to win the heavyweight title and engage in historical scraps vs. Jersey Joe Walcott and pushing Rocky Marciano to the brink of defeat twice.
Evander Holyfield: I'm sure I will get grief for this ranking, but Evander was hands down the greatest fighter ever at cruiserweight. He completely cleaned out the division and unified all available belts. What gets Evander into my top ten is his accomplishments at heavyweight, beating the big names of the second best generation of heavyweights ever and regaining the lineal title multiple times, the only other fighter not named Ali to do so. Beat fellow greats Tyson, Foreman and Bowe as well as solid challengers and fellow champs in Ruiz, Mercer, Moorer and Douglas. While Evander was inconsistent at heavyweight and remained active too long (suffering unsightly losses late in his career), his work at cruiserweight and historical wins at heavy (the Tyson win was epic while the Bowe rematch was impressive) put him just in my top 10.
9) Willie Pep: With all due respect to Pernell Whitaker, Pep is considered by most to be the best defensive fighter ever and fought much longer and was just dominant as whitaker, although he didn't have the success that Pea did at multiple weights. Was past his best when he engaged in his historical fights vs. Sandy Saddler, putting on a boxing clinic in their second fight. Pep was so good defensively that it has been stated that he once won a round without throwing a punch.
10) Pernell Whitaker: Second best defensive fighter ever, in my opinion, and in contention for best lightweight ever. Cleaned out a formidable lightweight division, unifying all of the titles and barely losing a round while dominating HOF fighters like Azumah Nelson. Won a title against the feared Rafael Pineda at 140, and when he couldn't force Julio Chavez to fight him, he rose up in weight and took on the #3 P4P fighter at 147, Buddy McGirt. After winning McGirt's title, was ripped off vs. ATG Chavez (draw) in fight everyone except the judges knew Pea dominated. Dominated McGirt in the rematch and went up again in weight to take on the much larger and respected Julio Vasquez, taking his 154 title. Whitaker was dominant at 147 but gradually deteriorated due to drug abuse and lack of training and lost a disputed decision to a prime Oscar de la Hoya. Whitaker suffered disputed losses to Jose Luis Ramirez at 135 (he avenged) and Oscar at 147, and wasn't clearly beaten until Tito beat him when he was well past his prime.
11) Archie Moore: 2nd best lightheavy ever behind Charles, who gets the nod due to dominating Archie in their head to head match ups. Archie was frozen out of the mainstream during most of his prime years due to the color barrier, but still went on to score some historical wins and engage in classic fights. Was successful to a degree at heavyweight, but was never able to win the title. I place Archie here for his longevity, the fact that he was frozen out of the big fights during his prime, his record for most knockouts ever (145 I think), and his overall dominance at 175 and contributions to the sport.
12) Bernard Hopkins: In my opinion, Hop is in for the discussion as best 160 pounder ever, with a record setting 20 successful defenses. Beat numerous HOF caliber fighters during his reign, most notably Felix Trinidad and Oscar de la Hoya. I feel Hop beat superior competition than Monzon and equal competition as Hagler, but what separates him from the other two is his success at the higher weights against formidable competition as well as his longevity. I can see why others wouldn't rank Hop as high, especially considering his style against speedy fighters, but when you look at his accomplishments, I think he warrants a high ranking.
13) Marvelous Marvin Hagler: One of the greatest middleweights ever, and one of the most feared fighters in the history of the sport. Hagler fought HOF fighters like Duran, Hearns and Leonard, and won what is considered the greatest middleweight fight in history, and one of the top 2 or 3 greatest fights of all time vs. Hearns. I place him below Hop because Hop had more defenses and enjoyed significant success at the higher weights even when well past his prime.
14) Carlos Monzon: Dominant middleweight who is also in the discussion for best middle ever, but in my opinion he didn't beat better challengers than Hagler and he didn't have the longevity or success at the higher weight class like Hop, whose historical feats separate him from Hagler and Monzon in my opinion.
15) Emile Griffith: One of the greatest welterweight champions ever who was also a dominant champ at 160. Beat numerous HOF caliber fighters and would be ranked even higher if he hadn't lost his killer instinct after killing Benny "Kid" Paret in their fight.


I left off fighters like Greb, Fitzimmons, Burley, Benny Leonard, Joe Gans...etc., because I honestly haven't seen enough of their fights and haven't read enough on them to place them above those I have in my top 15. That being said, Mickey Walker and Harry Greb were supposed to be BEASTS and were definitely terrors, as were Stanley Ketchel, Jack Dempsey, Ike Williams, Bob Montgomery...etc. For those who rank those guys in their top 15 or 20, I completely understand and think those lists are probably more comprehensive an accurate than mine.