The likelihood of there being other intelligent life in the universe - even in our galaxy - is pretty much a certainty in my opinion. Even if the likelihood in any one solar system is miniscule, the sorts of numbers we're talking about make it near certain that the universe is currently, and has been in the past, teaming with life. Basically the only real possibilities were lots of life, or no life at all... And we know that life does exist, because... Well... Here we are. Festering away on our smelly little pebble, hurtling through space