Difficult to disagree with you Dragon, although I'd offer up two more memories to vie with Hemery's gold and WR in Mexico City as the fifth choice.
Firstly, Mary Peter's gold in the pentathlon in Munich at the height of the Troubles in Northern Ireland in 1972, despite the IRA'S death threats against her. Sport was one of the few areas in which the communities could sometimes be brought together at that time as epitomised by people like George Best and Alex Higgins who enjoyed support across the sectarian divide. It's a memory that has often been repeated on the Beeb.
Secondly, Daley Thompson winning his second gold medal in the decathlon in Los Angeles in 1984. The back flip on the pole vault mat sticks in the memory and has often been repeated on TV.