In the news at the moment (September/October 2010) is this item about the discovery of an Earth-like habitable planet only 20 light years away.
Apparently, its climate is livable, if chilly, it could support liquid water and life not unlike Earth's, and it has gravity similar to ours and an atmosphere.
Twenty light years is right next door, in our galaxy of billions of stars, one of billions of galaxies. It makes astronomers think that the number of similar friendly planets in the galaxy has to be very large, as does the probability that some of them would harbor life.
Dr. Steven Vogt of the University of California, Santa Cruz, told a reporter "The number of systems with potentially habitable planets is probably on the order of 10 or 20 per cent, and when you multiply that by the hundreds of billions of stars in the Milky Way, that's a large number. There could be tens of billions of these systems in our galaxy." He adds: "Personally, given the ubiquity and propensity of life to flourish wherever it can, I would say that the chances for life on this planet are 100 percent. I have almost no doubt about it."
You may be sure Ana Darcy Méndez is not surprised. She suggests that scientists look more closely at star systems say, twenty-five light years from Earth. She will tell you there is no "almost" about the chances of a habitable planet at that distance. There is, in fact, a lovely planet at that distance. She knows from personal experience!
(See Stephen Hawking's comment about extraterrestrials here.)
(Asked about Area 51, Ana replies here.)