Honestly I have no idea. I assume there must be some kind of life out there, even if only primitive pond scum or something. With that said, I won't be convinced that aliens have actually visited us without some kind of proof or first hand experience. I put that idea in the "I want to believe" category alongside paranormal activity, bigfoot, etc.
Part of the issue is we've never even found evidence of primitive alien life, therefor we have no idea how likely the emergence of life is. Do you just add the right chemicals, add water and heat, shake and then get life? Or is it something much more complicated than that? There might be millions of habitable worlds out there where life never arose to begin with. We have no data to suggest that life is a common occurrence at the moment, nor do we even know HOW it started to begin with. Even creating a simple single cellular organism through random chance seems incredibly unlikely. You need DNA to store the information, but that DNA isn't useful for anything without the rest of the cell, and you can't get the rest of the cell without a DNA guided cell division. The ultimate chicken and the egg problem.