The greatest game ever played is the one marketed with that tag by Australian Football Video: the 1989 round 6 match at Prince's Park between Hawthorn and Geelong, an awesome display of the skills of the game. It is doubtful whether two such great sides had ever graced a single season as the Hawks and the Cats did in 1989. The return match in September was a bit of a purler too, as I recall.