Putting a man on the moon: Priceless?

According to the assumptions of this article, the Dawn mission is part of the price of going back to the moon. Currently, I'm a believer, but in practice an agnostic, in NASA's new overriding mission. On the one hand, can anyone really foresee a future without men exploring space? And if, as I expect, you can't imagine people not roaming ever further in space, shouldn't the U.S.A. be on the forefront of this exploration? With China, Japan, and who knows who else re-engaging a space race, now is the time for us to go as well. On the other hand, I wince every time a credible and important space mission has to be scrubbed due to funding, and the linked article provides just such a mission that came under the axe due to NASA's reorganization. Perhaps in reality the cost overruns and technical difficulty would have scrapped this work anyway; it doesn't really matter. Missions like this will be canceled so men can stretch their legs on Lunar (and hopefully Martian) soil, so the message is the same regardless of the details. I'm still a believer, but the costs, both financially and to scientific advancement, are not negligible.