This is a Post of Unmitigate Geekery(tm).
Well, actually, let's say mitigated geekery, because it's a topic in which I'd love to be competent, but am not, and that is astronomy and orbital mechanics.
According to New Scientist, which I'm too cheap to pay for (though it's a darned fine magazine), one of the fuels on our current horizon is powdered metals, particularly iron. Makes sense: folks have talked about turning the Al2O3 on the moon into rocket fuel for years.
Great! Um, now what?
Well, I was mulling over the notion of "how do you have a reasonably coherent Sol economy, and started looking at what asteroids were made of. (Yes, asteroids. People going to moons and planets is too obvious, given what a friend says about the obvious cultural imperatives of Martian horses.)
Let's take Golevka.
And why not? Golevka's pretty cool. It's a giant rock shaped sort of like what you get when you clumsily mate a pyramid and an acorn. Now, realize, by "giant," I mean as compared to, say, the stuff in your average quartz garden. Golevka is the 4'2" spunky hobbit of the asteroid world. It's a silicate asteroid, highly irregular in shape, almost certainly containing olivine, a basaltic rock made up in large parts iron and oxygen, and may contain quite a bit of magnesium as well. At an estimated five grams per cubic centimeter, for an object that is, roughly, 350x250x250 meters, that's roughly 12,000 tons of processable material (a bit more massive than a nuclear-powered cruiser), some of which can be put to use sustaining atmosphere, and some of which can immediately be put to use for either fuel or structural material.
Okay, that's still not solving your whole "I like gravity" problem, even though Golevka does come fully-equipped with highly-variable gravity, meaning it's a lot easier to get into orbit around it from one one end of it (the skinny one) than the other. So, um, what gives? What's the point?
Well, if you've got Celestia or some other ephemera, it becomes obvious pretty quickly, but if you don't, check this out. It's a cool little rough orbit simulator. Turns out that Golevka has an interesting little orbit, that brings it mightly close to our favorite Blue Marble(tm), all the way out to within spitting distance of the main stretch of near asteroids. Equipped with some kind of mass driver, and made capable of receiving packages sent the same way (or by means of a space elevator sling, which is made simply by extending your elevator past the stable points until the far end whips around with plenty of energy), Golevka would tend to be in a good position to do basic commerce. Equipped with supplies, fuel, and a medical staff, not to mention a really extensive rack of movies and hot dogs, she also tends to turn into a pretty decent way-station, and a cheap, slow-boat means by which one can get out towards the Jovian moons, or back, without actually owning a vessel.
In other words, once we're wandering through the black on a regular basis, this dinky little asteroid has commercial and strategic value. Probably not military value, but it has serious potential as an interplanetary truck stop.
Truck stop... Rock Stop?