They'll never be another fighter with more heart than Evander Holyfield. Always a warrior. Shame so many people make jokes about him on this board. If you actually had the opportunity to watch him coming up through the ranks in the mid to late 80's you wouldn't be so disrespectful as many people here are. Kids.
Roy Jones is the obvious answer. I also think that there WILL be another Tyson to come along one day - and by that I mean the drawing power, the story behind the man and the talent in the ring. He obviously wont be a Tyson clone but there will be comparisons made. My pick however would be Evander Holyfield.
It's nice to see people mentioning Holyfield. It really is cuz he's one of a kind. You can say what you want about his religious beliefs or his shortcomings as a man (God knows we all have them) but you cannot take away from the fighter that he was.