Not a fan of 4th Edition Dungeons & Dragons. The core rule books bore me, I can't feel at home in the 4E community, and I have no use for encounter-driven gaming.
But I'm willing to forgive Rob Heinsoo, lead designer for 4th Edition, for all of that because he has bestowed upon the world the following brilliant advice that has fueled my creative endeavors since I first received it several years ago. Check it out:
... for me, moments of innovation come more often when I'm thinking about a particular group of people I want to play a game with. I get a clear vision of the game we would have the most fun playing together. ... Writers learn to consider their audience, to think about the people they are writing for as if they are reading their work aloud to that chosen audience. As a game designer, you may be just a bit luckier than a writer, because nearly all games are already group efforts or social experiences. ... Phrasing your goal in this manner is more important than it may sound.Damn straight, Rob. Damn straight.
For further edification I recommend his article "Sieze the Hook" in the Kobold Guide to Game Design. Worth every damn penny.
UPDATE: And what's this now? EnWorld is reporting that there's a new Kobold Guide to World Building out this week. And it's on sale at DriveThruRPG! Your timing is impeccable, #2...