It's strange to hear so many people suggesting that story generation and world generation are separate things. For me, they are highly dependent on one another; maybe I'm just too influenced by Tolkien but my worlds tend to share Middle Earth's property of containing, within them a powerful metanarrative around which play will inevitably centre.
For me, creating the story arc for a campaign and creating the world in which the campaign will take place are one in the same. I think that's one of the reasons published settings leave me cold so often; some poor designer has had to create a world with no implicit narrative. Or, worse still, a world built to tell one story has been hijacked to tell another (of course the best example of that is in fiction with Ursula Leguin revising/ruining her own creation with Tehanu).
For me, creating the story arc for a campaign and creating the world in which the campaign will take place are one in the same. I think that's one of the reasons published settings leave me cold so often; some poor designer has had to create a world with no implicit narrative. Or, worse still, a world built to tell one story has been hijacked to tell another (of course the best example of that is in fiction with Ursula Leguin revising/ruining her own creation with Tehanu).