Gameplay!

Um... Gameplay. But if the story sucks and is too short am not buying it.

Gameplay, but if the story is dumb and weak then there is no point in playing, it just feels boring and lifeless.

While that is true for most games, I'm pretty sure something like Mario wouldn't really be called exciting in that story area, yet people love it. Same thing goes for most platformers,fighters,or puzzle games. I think it fits certain genres.

depends on the genre, i am big legacy of kain fan, the story is one of the best but the gameplay was below average still enjoyed the series thanks to the amazing story, and when i play game like mario i expect very good gameplay i don't even pay attention to the story.

My favorite game stories are usually RPG type games.  I really enjoyed FF4, FF6, FF7, and Super Paper Mario.  About Bioshock, it's story was worse than bad, it was evil. The story is partly about how freedom is bad.  I could never play a game like that, but I did hear that some people liked it (no suprise there).

If Ratchet and Clank didn't have a good and funny story it would suck :P

But yeah, my statment is mostly directed toward shooters and RPG's.

Gameplay

Either can make or break a game.

Any game with excessively awkward controls, poorly designed interface, rough play mechanics, and poor response is going to feel unplayable regardless of how interesting the story is.

Best case scenario, the player will find himself learning and compensating for the inadequacies of the interface in order to finish the game and see how the story develops and ends.

With good game play, it is still very possible to enjoy a game while ignoring virtually everything else, even if the game feels dated (primitive visuals or play mechanics) or the story underlying the game perfunctory (rescue the Princess, defeat/kill the Bad Guy, repel Evil Army).

A pointless, or weak story providing no reason to play through the game only has high score or best time as motivation for the player to keep playing. Fortunately, that's still enough to keep most players engaged.

Story first for motivation, and then gameplay. The gameplay must exist though or else I wont play it no matter how good the story. Without a story its empty, without gameplay its just broken.