I believe that there are so many planets and stars in the Universe that it is very likely that there is some form of alien life somewhere out there. I don't believe in grey men or reptile creatures.
It would be either downright arrogant or extremely stupid and narrow-minded to believe we are the only intelligent beings among nearly 12,000 GALAXIES in our (observable) universe, alone. That said, I hope nothing more advanced than us ever decides to colonize.