The metric for making this choice should be on how well the console performed commercially as a result of the software (how much of a role the game played in achieving said numbers). Anything less, like how good you felt it was, how fun it was, whether or not it was better than this or that... is looking in the wrong direction. You judge a launch title by its ability to get units into homes, and nothing else.
Super Mario Bros. is that game.
Why?
Because unlike Wii Sports and Tetris, Nintendo was an unknown brand to most of the world. There was no precedent, no consumer confidence or familiarity to aid in sales. You had a brand new, unknown console coming out of a foreign company right after people had decided to walk away from the entire industry. And yet look what happened. And it's all thanks to the power of the plumber.
When it comes to launch titles, SMB stands alone, imo.







