Judging by: -Crowd size, -Television audience (if any) -Social importance, -Overall publicity, please take into consideration that boxing actually existed before DeLaHoya, Mayweather and Pacquiao
The first two that came to my mind was the Ali/Frazier fight (Thrilla in Manila) and the Ali/Foreman fight. I know there's more.
Holmes-Cooney was huge. You could not pick up a newspaper or watch TV without seeing it being mentioned at the time.
good call rico. i'll agree with ali-frazier 1 and add tyson-mcnelley, johnson-jeffries, dempsey-carpentier (dodger vs war hero, BRILLIANT!)