An e-mail discussion with my old friend and current 4e DM has been illuminating. We talked about rules crunch and fluff in supplements and while he came in favor for more rules to give more character options and more detailed world background and fluff to give some shape to fantasy I came down on the side of fewer rules and much less fluff (which probably is no surprise to regular victims of the blog.)
What strikes me is that my old friend is a long-time "storyteller" DM as well as a budding writer. Part of me actually thought that he would have chosen the route of less crunch (more room for storytelling over tactical play) and less fluff (more room to strut his writerly stuff)-- but actually listening to him, it is his writer's instinct that pushes him toward liking both fluff and crunch. He chooses rules complexity to allow definition of characters on paper, and world background for setting definition on paper, and setting forth an established character and background that then interact in play, but with a set canon on which to build.
I tend to take a different approach to the whole game. My basic argument is that the game doesn't exist outside of the interactions between participants. There is no plot but the action of the characters, there is no real setting unless it is encountered in game, there is no character but what people experience in game. Now, I think that "in game" can be expanded beyond the tabletop through things like in-character journals or logs shared with the Referee and the group, shared tales of past exploits and the like, but for most groups, this kind of expansion of the game seldom happens.
It's not like we can't get together and have fun despite this difference, but it's interesting how fundamental our differences are in approaching the DM role.