I don't know enough about the fighters you've mentioned to compare Calzaghe to them, but I've recently been watching some of his old fights (if anyone knows where I can find the Eubank fight send me a PM) and there is no denying Calzaghe's skill, the only debate can be about his level of opposition.

He is legacy will always be debated because he did not have any internationally defining fights until the very end of his career. Lacy, Kessler, and Hopkins were all great wins for Calzaghe, though I though Hopkins beat him by a round, but I really think if the opportunities had presented themselves earler he would have been able to establish himself as an largely undebatable all-time great.