I agree Eubank all day long..the other 3 are debatable and maybe i'm biased because I have such good boxing memories of Eubank when I was younger but I still believe Eubank to be a cut above these 3. Eubank was a classier and technically much better boxer than both Benn and Collins..and like Bilbo said earlier, regardless of how Eubank Watson 2 was going..Eubank came up and closed the show in spectacular fashion. End of the day he WON.
If I had to i'd go 1)Eubank, 2)Benn/Watson (interchangeable with 3) 3) 4) Collins

and I also disagree Calzaghe would have beaten all of them if each were in their prime..I still see Eubank being too clever in his prime. Collins even might have had that rough style to give him a good fight. Benn's power would have troubled him if Benn could land.