Joe Louis, Max Baer, Rocky Marciano, Sonny Liston, George Foreman, Earnie Shavers if he caught him right, Larry Holmes might have stopped him over 15, Mike Tyson, Ray Mercer, and Lennox Lewis(already did really) would have had a good chance of stopping Vitali.
Valuev would destroy Vitali in his prime. Now, he still might, but probably grind out a decision on a Vitali that's running for dear life, or should I say "deer" life, because he'll be like a frightened deer in the sights of Valuev's dreaded fist rifle!
Silly delusion. Could, would? Watch Vitali beat all your heroes. Tell you idol Haye to quit running and fight.
I think Vitaly cannot be stopped by one single punch, you would need to pressure him for rounds to send him to the canvas. I see prime Lewis by a late stoppage, but Tua and Markovic could go 12 rounds, so who knows. I think probably prime Foreman would have the most chance to do it. But Vitaly has a granit chin and the only reason Sanders could rock him was that it was the very first round, the chin has to "heat up" as well. The punches he received from Lewis sent Tyson down.
It is the old guard vs the new and traditionally the new blood wins to take over. I bet almost every single Lewis opponent watched that fight wishing that that was the Lewis that they faced instead of the focused master boxer/puncher that beat them. It was the fight that Vitaly dreamed of and he couldn't close the deal.