IIRC, Kepler 22-b was the first planet found where water is likely to be liquid that isn't also a gas giant. A number of sci-fi entries reference it as a result.
It's probably still not habitable by people though, given that its gravity is ~2.5 times that of Earth and is furthermore probably covered in a worldwide ocean.
Current research suggests that most worlds with liquid water are, unlike Earth, probably entirely covered in liquid water. Opinions differ if intelligent life trying to leave such a planet would have merely a much harder time than us or be flat out impossible (no easy access to fire and smelting, only dissolved gases in water, etc.) Cetaceans (dolphins, whales, etc.) are some of the smartest creatures on Earth and have squat for designed tool use, and they aren't even fully aquatic. (Some Cetaceans will use other animals directly as tools, like wearing soft sponges on their nose to protect from sharp coral, but have developed no tools of their own.)