Quick Google reveals we can thank NASA research in part for some thermal insulating materials, cleaner-burning jet engines, tap water purifiers... New missions will undoubtedly lead to advances in solar and fuel-cell power if nothing else...
Plus, as "rational" as it is to instead throw all those additional billions of dollars at social problems (and we are well on our way to solving those with the money so far spent, right?), people discount the immeasurable "halo effect" that a manned space program to say, Mars, would have on today's children and their interest in science. (Look at the effect of the rovers.)
I say we need a self-sustaining colony somewhere other than here, in case of big space rock, remote-but-still-possible nuclear armageddon, or other cataclysmic event.
BTW, how much colonization or mining (mass addition or removal) can the moon stand before the orbit changes (more than it is)?