For me, it's Super Mario World! Super Mario Bros 1, 2 and 3 were good of course and we played them a lot (especially nr. 3), but I remember when the Super Nintendo was new. I wanted one
so much and the game that came with it was of course Super Mario World. I wanted that super nintendo more than I'd ever wanted anything and when I got it, I played the crap out of Super Mario World, Legend of Zelda : A Link to the Past and also eventually, Super Metroid .. The three best games for the console.