Next Door Neighbours?

Yes, we've heard about the recently discovered 'rocky planet,' (COROT-Exo-7b) and the fascinating insights it may have to offer into planet formation, but to be honest, it doesn't sound like the kind of place you'd want to set foot on. Which raises the question, "What kind of planet would people want to set foot on?" Presumably, for the sake of comfort alone, that planet would be as Earthlike as possible. Although the temptation of dipping your toes in an ammonia atmosphere appeals to curiosity, the novelty might soon wear off, and then what? The great adventure of exoplanetary exploration is finding and colonising a planet capable of supporting terrestrial life. According to this article http://planetquest.jpl.nasa.gov/news/nextDoorNeighbor.cfm there's a good chance (or, at least, a $100 bet) that a habitable, Earthlike planet lies in orbit around the nearest star system to our own, Alpha Centauri, at around 4.4 light years away. As far as human settlements in space go, we currently have the International Space Station with rotating crews, and some much debated possibilities of establishing settlements on the Moon and/or Mars. As an ingenious species, we've demonstrated that we are capable of travelling through environments extremely hostile to life as we know it, by 'bottling' a friendly environment, and taking it with us. Experiments like the Biosphere 2 project have deepened our understanding of what it might take to 'bottle' a whole, functioning ecosystem, humans included, and set up home in a permanently hostile environment, whether that 'bottle' take the form of an orbital space station, a lunar or martian colony, or a deep space exploratory vehicle. However, the ethics of doing so aside, we have yet to locate a destination at which it would be possible to 'uncork' such a bottle, since environmental conditions around the ISS, on the surface of the Moon and Mars could never support human life unprotected. Think 'sparse atmosphere' and 'unmitigated cosmic and solar radiation.' Even low gravity is probably bad for our health, in the long term. So, if we're really venturing out into space to establish permanent settlements, do we want to do so in a bottle that we could never truly leave, only expand in scale, or do we want to find a place to open our bottle, a planet with a dense enough, nitrogenous atmosphere (we could make our own oxygen, once we got there, if there's none there to begin with) and an active core generating a protective, magnetic field to cut out harmful levels of radiation? A place where we could, eventually, take a deep breath of fresh air, swim in a lake, bathe in the sunlight. And what if such a place were just right there, around the next star system over?