plutherus

Oh, yeah.
An international conference of scientists, engineers, and mission planners met in Hawaii last month.
Yesterday, they released their declaration calling for an international coordinated effort to set up permanent bases on the moon.

They listed many reasons, primarily commercial exploitation, which I don't think would really be cost-effective. Anything mined from the moon would cost currently a whole lot more to send back to earth than just mining the same things here. They did, however, also mention the slightly less material goals of "...to establish a second reservoir of human culture in the event of a terrestrial catastrophe, and to study and understand the universe."

The barely skirted my favorite reasons: in the long term, we have to go out to space if we're going to survive as a species. The Earth won't last forever, even barring any more giant comets slamming into us (one doesn't have to destroy the Earth to really suck for us. Another one that kills off 90% of species would make our future pretty bleak, and those have hit a few times before). There's a thousand other things that could happen, from out-of-control pollution, gaian collapse, the eventual death of the sun, etc. If we wait until catastrophe is upon us to start going out there, it'll be too late. And the gods only know how long it'll be before we destroy our civilization ourselves and what'll happen in the meantime before we rebuild to this point again.

In the shorter term, though, Dr. Robert Zubrin pointed out one of the best reasons a couple of months ago when he testified before the Senate: In the 60's the number of science and technology graduates more than doubled. In the 70's and 80's, they went back down to pre-Apollo levels. A real goal in space would be a huge visible event that would inspire countless people: encourage them to study science and technology, seeing something they could actually apply it to when they graduate, and showing a future that could be brighter than just endlessly repeating our cycle of which nation is the prominent empire this decade. Though I'd like to see a commitment to the slightly longer term goal of building Mars colonies, a base on the moon would be a good first step.