So far we know many potentially habitable planets around other stars out of nearly 2,000 planets that have been detected and confirmed. We expect to find many more in the following decades. Unfortunately, we are very far from really understanding the potential for life of these planets since we know very little of them.
We have a rough idea or their size and temperature and that tells us how likely they are to support liquid water, a necessity for life as we know it. However, we also need to understand their atmosphere, water content, climate, and many other factors that are still out of reach of our observational technology, these planets are very far away.
A habitable planet does not mean that it is actually inhabited, only that it might support life, at least microbial life. It might be hard to imagine a planet able to support life yet not inhabited, but that is another possibility. Some might be better than others since their habitability depends on complex physical and chemical interactions. If the planets already have life, well, that is another complication illustrated in the movie HOME.
Home is a 3D computer-animated family film by DreamWorks Animation scheduled for release on March 27, 2015.
Spanish Version: Casa es una película familiar animada por computadora en 3D y creada por Animación DreamWorks para ser estrenada el 27 de marzo de 2015.
ps I use this movie trailer to introduce the concept of habitable planets to kids. It works like a charm.