In order to have life on a planet (let alone intelligent life), you need a medium sized star containing the right amount of metals and hydrogen, a planet with the right amount of mass, the planet has to be at the right distance from the star,the planet has to be in a nearly circular orbit, the planet has to have enough water and nitrogen and carbon, and a gas giant farther out to deflect comets wouldn’t hurt.
We have detected about 200 extra solar planets so far, and only a handful have some of the above criteria (two of the stars are called 47 Ursae Majoris, 44 light years away, and Gliese 777A, 52 light years away www.extrasolar.net These two star systems have Jupiters at the right distance for comet deflection and would be stable with an Earth-like planet closer in).