I'm biased in saying 1997 ARL, but ultimately it has provided images and evokes feelings about Rugby League that saved the game in all honesty. Super League really did nothing and was dominated by 1 team. Whilst Manly were by far the best team of the competition, it was that game that got people genuinely interested in Rugby League again.
1989 would be just outside the 15 year barrier in the question, but it was a great game of footy as well.