What Comes First: Gameplay or Story?

When designing a game, particularly a role-playing-game, which comes first: the story or the gameplay? Think about any RPG, is the story more important or the gameplay? Regardless, which aspect is the primary design point?

In an interview with IGN, Eisuke Yokoyama talks about the development of Final Fantasy XII: Revenant Wings for the DS.

We did not set out to make a game that was connected to FFXII. In the beginning it was supposed to be a 'My first Final Fantasy' experience - that was the overall plan for this game. We had already created the battle system. It was ready to go, but at a certain point during the development and planning process, Toriyama's team started talking. FFXII had just been released and it was really popular, so it was more a matter of timing that it turned into this kind of game.

I was surprised to read this. I actually don't think there is any one order to design an RPG, or any game, for that matter. Whichever comes first comes first. If you come up with a great story that would work well with a video game, congratulations. But I think its probably equally effective to come up with a gameplay system and then build a theme and story around it. Both aspects are very important, however. Whichever comes first, in the end both need to be given equal consideration and development. An RPG needs both to be truly great. Personally, I almost always design the gameplay and control scheme before even thinking about anything else. But who knows, maybe one day that will change if an interesting story and world suddenly pop into my head. Both approaches are entirely feasible. Which foot do you start off with, gameplay or story? And do you think one approach is superior to the other.