Barbosa was spot on. Melee was a riot with some friends, and quite decent on it's own. The trophies, secret characters and other features were pretty good and kept me playing for many hours.
But Super Mario World is as perfect a platformer as you'll ever find. The innovation, the design, the controls, the secrets... It was simply a magnificent piece of art. If I could only play 3 games for the rest of my life, Super Mario World would be one of them. Even if you've finished the main levels a few times, the amount still left to find in the game is mind blowing, especially at the time it was released. It has more nooks and crannys to explore than most sandbox games, and that's very impressive for a 2D platformer.
SMW all the way.