24 Jan 1998 V Bristol City at Ashton Gate. About 600 (of over 14k attendance) of us witnessed one of the best 0-0 draws I have ever seen. City finished second to Watford that year, we were fourth behind Grimsby who beat us in the play off final. Cobblers were applauded off like Champions after a very battling and entertaining performance to earn a point against one of the top teams in the division.
In a similar vein to this, the game at Man City which also finished 0-0 was a real battling effort, though we did get battered for most of the game, but I think that was the following year when we got relegated. Cracking atmosphere though.