Kepler-22b
"If it is mostly ocean with a small rocky core," Natalie Batalha, one of the scientists on the project, speculated "it's not beyond the realm of possibility that life could exist in such an ocean." This possibility of life has spurred SETI to perform research on top candidates for extraterrestrial intelligence. However, if the planet's carbon cycle has ceased due to lack of oceans and plate tectonics, Kepler-22b may turn out to be a searing, sterile super-Venus.