IMO. (In no order) Mayweather Jr. (Defense/Counter Punching) JM. Marquez (Counter Punching/Combinations) Manny Pacquiao (Attack/Angles/Balance) B-Hop (Experience/Defense/Tactics) Vitali Klitschko (Ivan Drago)
Mayweather is far & away the most skilled fighter in boxing, everyone else takes 2nd place. Pac would likely be that 2nd place tho.
Pacquiao Mayweather Hopkins Marquez Martinez I'm not completely sold on Ward yet, and although I do rate Dirrell I am unsure of what to think of him at the moment. A very clear top four, you could argue about 5th spot, but I thought Martinez's display vs Pavlik was superb, even though I have my reservations about his technical abilities vs someone who could match him athletically. PS: I don't count Toney, Jones, Holyfield, Morales etc as actually being active, they're pale imitations of the fighters they were.
Floyd Jr JMM Ivan Calderon. Lara. Manny(different but skilled) Martinez (again, different but skilled) Not saying this are the top guys. Just guys I loved to watch.
Pacman and the Klit brothers. Their opponents have been beaten and humiliated without even laying a glove on them. Guys like Haye, Povetkin and Mayweather would rather live in humiliation then get in the ring. When you can make an opponent forget he is a man and become a little ***** girl, without even putting the gloves on, you have gone past ordinary skill.