Not all of them need awesome storylines to have great playability:

Zelda: Guy has girl, Guy loses Girl. Guy must find Girl.
Mario: Guy has girl, Guy loses Girl. Guy must find Girl.
Gauntlet: Shoot stuff. Shoot stuff. Shoot stuff. Archer needs food. Shoot stuff. Shoot stuff.

What about games with ridiculous "stories" like:

Pac-Man: What story is there here? Yellow dot eats little dots, runs away from colored ghosts.
Asteroid: White triangle shoots at lined objects with a line.

Not all great games need amazing storylines, although they can certainly help matters (Resident Evil, Silent Hill, Max Payne).