The one thing in there that was new, or at least a point I'd never considered in quite so clear and elegant a manner, was this (a quote from Bruce Sterling) :
I'll believe in people settling Mars at about the same time I see people settling the Gobi Desert. The Gobi Desert is about a thousand times as hospitable as Mars and five hundred times cheaper and easier to reach. Nobody ever writes "Gobi Desert Opera" because, well, it's just kind of plonkingly obvious that there's no good reason to go there and live. It's ugly, it's inhospitable and there's no way to make it pay. Mars is just the same, really. We just romanticize it because it's so hard to reach.Obviously, there are two comebacks to this; we would try to inhabit the Gobi Desert if we literally had no choice in the matter , and we'd probably be far happier to try it if the Gobi Desert proved to be sitting atop, say, massive gold reserves (I know we haven't found anything compelling on Mars yet, and it's hard to imagine anything being worth the cost of the trip, but...). Still, it's an excellent point, and as Stross notes, even the sudden discovery of pure awesometanium on Mars still won't make anyone want to stay there, any more than oil-riggers in the North Atlantic decide to stick around once their shifts are over.
Anyway, the whole thing is well worth reading.
(Image by Lynette Cook)
 The only part of the analysis I find particularly questionable is the idea that we should have no personal interest in the survival of the species after our own deaths. Whilst I understand how one could believe that, and even grant for the sake of argument that such a position is the most logical one to hold, I think arguing against such feelings is pissing in the wind as far as human nature is concerned. You might as well argue it's stupid to want to save cute puppies when there are so many ugly, ugly dogs still unsold.