The first and most mundane of my choices is Eberron, the established, quasi-official setting for 4th edition D&D (which is what we're playing.)
- Very well characterized regions and factions; means I have to make less stuff up. (I'm actually not much for the creation of settings out of whole cloth; my view is, the more work I can put into plot rather than setting pamphlets, the better.)
- It is by far the most beautifully steampunk setting I've ever heard of for DnD. It's got zeppelins, people. Zeppelins. The flying transports I'm so fond of that I named my blog after them.
- It is high-magic, and will support screwball plots like the current contender for my campaign: the PCs play a fantasy police/Drug Enforcement Agency, tasked with jobs like intercepting Polymorphine shipments and confiscating +4 Wands of Murder from hardened criminals. Don't look at me like that.
- I am a very lazy individual. As such, I don't want to read through the hundreds of pages of Eberron campaign materials.
- My players are very lazy individuals also. See above.
The Real World
- No work needed AT ALL for setting, since everybody understands how it works in terms of law enforcement, currency, social norms, etc. The players are as intensely familiar with the setting as the DM is. Even moreso if you base the game in your hometown. (The maps are all drawn for you!)
- I've actually seen this worked to great effect in World of Darkness games (well, okay, really just Orpheus.)
- We'll be playing DnD 4th edition, which means I'll need to finagle a plot incorporating warlocks and sorcerers into an Earthlike setting. (Particularly since DnD 4th ed is pretty sparse in terms of purely mundane classes, like the Fighter and Warlord.)
Style 1: THE MASQUERADE!
- This is the assumption the World of Darkness games works under: that basically, the supernatural exists, but normal people/"muggles" simply don't know about it. This ignorance is carefully cultivated by the Powers That Be for their own ends. Advantage: Justifies PC knowledge of American culture/technology. Disadvantage: I'd need to work out a mechanism for enforcing the Masquerade.
- In this style, the PCs are going dimension-hopping for the sake of going after a MacGuffin! The powers they wield are completely unknown to the Earth; hilarity ensues.
- Advantage: Plenty of possible reasons to be doing this. The important thing is, this type of game gives you the opportunity to live the American dream. Which is to say, fireballing the DMV. Disadvantage: It's a fish-out-of-water scenario for the PCs, who likely don't have a justifiable in-game reason for understanding things like ATMs. Or guns. Or the DMV.
- Nobody has the PC's kind of power, but they are also native to the earth. They've been given magic powers through some kind of ritual or event that really just doesn't happen that often. The reason that magic isn't well-known is NOT that it has been kept a secret; it's just that it's hard enough that the few who practice it are taken for cranks and ignored. The Dresden Files uses this one, actually. Disadvantage: I have to figure out why the PCs are magickers in a nonmagical universe.