Going to go against the grain and say Atari to NES.
The graphics themselves were a pretty big jump. But just as importantly, the NES had what could actually be considered music. And more important still, it allowed for larger games that allowed for actual progression in gameplay. I'd say going from games like Space Invaders and Pong to things like Zelda, Metroid, and Mega Man 2 is an even bigger leap than going from Super Mario World and Mega Man X to Ocarina of Time and Banjo Kazooie.