This is a good thread, it's cool to see what people think across multiple decades... I'll go with my top 5 in order of what they meant to me:
5. Opening day game against the Jets 1986 - Jim Kelly's first game, and the expectations were so high the city was about to explode
4. 2000 revenge game against the Titans, I haven't been that amped up for a rematch in my life, I was at the Music City Mistake game
3. 1990 win over the Broncos... within 77 seconds that game changed completely, and I thought for sure it was a loss.
2. 51-3 dismantling of the Raiders
1. Bills - Oilers 1993 playoff game - self explanatory, greatest game I have ever watched.
I'm sure not many will put a Bills loss on their lists, but that 1986 opener was electric, you couldn't calm your heart down just thinking about what Jim Kelly was going to do for that team.