Each and everyone of these fighters with the exception of Bute has beaten more proven fighters than Kessler. I would take Calzaghe to beat everyone in that list, even Haye, if we're talking the Calzaghe who beat Kessler. Kessler, I wouldn't take against any of them, I think he's overhyped on this forum. A strong solid boxer and a champion in his division, but nothing more.