Scientists discover potentially habitable planets
We won't go to the stars until we're actually IN space.  Not visiting, but there permanently.  When people are born, live and die without ever being dirtside on Earth; when they live in habitats made from lunar and asteroidal materials, we're there.  When we've colonized this system we will be prepared to reach out to another.Now imagine these people, who've lived all their lives in wonderful space habitats, worked in ships and on other planets and such.  I don't think they'll be looking for another Earth.  Why would they?  They'll think their space habitat is far more comfortable.As far as interstellar travel is concerned, I'm certain we will solve longevity well before we travel to the stars.  FTL won't be the big obstacle it seems now.  When your lifespan is several centuries, spending 30-50 years of it traveling across the stars is as reasonable as our ancestors crossing Europe, the Atlantic or Pacific oceans, or the American Continent to colonize a new land.Since their colony ship is a fine habitat, they won't be looking for an Earth-like planet; they'll be looking for a Sun-like star.  Of which there are many.  Humans can spread out at a sub-light speed across our arm of the Galaxy.  But most trips will be one-way.  Each colony must be self-sustaining.  The best find would be an asteroid belt in the habitable zone.  Cheap resources!