a few others:

Hearns Vs Pipino Cuevas: Cuevas legs went all rubbery and wobbled for like forever.

J.Jackson Vs. T.Norris: Norris was outboxing him, then went flat on his face

Roy Jones vs Hill: kidney shot. always intersting when a fighter gets KO'd to the body

Hopkins vs. ODLH: ditto

ODLH vs Quartey: not a knockout, but the left hook that put quartey down in the final round was the difference in the fight, and one of the most dramatic punches in history.

Frazier Vs. ALI I: that left hook. no KO but beautiful to watch and perhaps the most famous punch in history

roy jones vs Kelly: the behind the back punch