The recent discovery of large deposits of almost pure ice on the Martian poles is exciting. Mars is extremely inhospitable, with a good Martian day looking like a warm day in Antarctica (minus the fish and the breathable atmosphere). Even so, the discovery vastly raises the odds of human beings being able to create self-sustainable colonies on Mars at some point in the not-to-distant future.
We need to stop throwing so much money away on things like Operation Iraqi Liberation and work harder at setting up some pockets of human habitation away from the Earth. In addition to the practical ends of such a mission, few historical accomplishments (except for the discovery of intelligent extraterrestial life) could have such repercussions on human consciousness. It's an exciting thought: we could be looking out into space knowing that we were out there. And this is one place where we could put our knowledge of how to induce global warming to good use!