Depends. If you're into RPGs, then get the Final Fantasy games, the Breath of Fire games, Secret of Mana, Illusion of Time, Shadowrun, and Terranigma (some of the best games ever, on any system ever made).
If you're into action and stuff, I'd say Rock and Roll Racing, Zelda, Super Metriod, Street Fighter 2 (original, not turbo or anything) and yeah Super Mario All Stars is damn fun, even nowadays.