The release date of Sonic the Hedgehog 3, coinciding with just about the highpoint of Sega's market share in the North American console industry, this was also right before Nintendo's streak of hits in 1994 (Super Metroid, Final Fantasy VI, Donkey Kong Country). After that it was all downhill for Sega.
Anyone else agree or have another idea on a date? (I know some are thinking September 9, 1999, but Sega's market share was MUCH lower then.)