When I'm running, I tend to make a setting using re-skinned bits and pieces from other settings and modules. I might have a city that is inspired by Baldur's Gate here, then a port town inspired by this or that (I'm a shameless thief!).
Outside of this, though, there are two settings I'd love to run a game in sometime: Magic the Gathering's Multiverse, and the world described in the Spice and Wolf novels. The former needs no introduction here. The latter features a low magic world with a focus on the intrigue of merchants and trading guilds and similar organizations, in which everyone is motivated by wealth and power (especially to the detriment of others).
Outside of this, though, there are two settings I'd love to run a game in sometime: Magic the Gathering's Multiverse, and the world described in the Spice and Wolf novels. The former needs no introduction here. The latter features a low magic world with a focus on the intrigue of merchants and trading guilds and similar organizations, in which everyone is motivated by wealth and power (especially to the detriment of others).