I think alien life does exist, although not necessarily Greys with big black eyes- I think, given the huge scale of the universe, and even our galaxy alone, alien life has to be out there- whether it is intelligent or not, is another matter, but in some form? Yes.

There have been several places in the universe that lie within a "Goldilocks zone" in which life as we know it is possible. So just on that we know life exists elsewhere as about 54 zones all failing to produce life is next to impossible. And that is just life as we know it, organisms based on carbon are all we know of so far. Who knows what the future will bring.

Yes, they do. I saw a few standing around Home Depot looking for Manuel Labor. Wait.... are we talking the same thing? ;)

There are 10^21 stars in the Universe approximately. By comparison there are only about 10^19 grains of sand on all of Earth.

Given that it seems most start have planets, even if life forming is like 1 in a trillion chance there would be billions upon billions of living things outside of Earth.

I doubt any have got this far, given the distances and speed of light problem, but maybe something out their will figure it out someday.

Belief in Aliens is the converse to belief in God. Like was said before me there are 10^21 starts in the sky, and even that is probably low-balling it. Most star systems have some form of celestial bodies in them. There is a group of students and professors at Oxford (I think, it's definitely a university in England) that are devoted to thinking of ways alien life might manifest. You don't have to subscribe to the Ancient Aliens theory to accept that the simple odds say that somewhere there's something else out there. So this is like the opposite of the God debate, as we understand science more we see God in the picture less and less, as we find out that the universe has all these rules that led to the creation of everything. With aliens, the more we understand about the universe, the vast distances, the massive amounts of stars in the sky, and now rogue planets which apparently escape the gravity of their own stars all the time, it becomes more and more likely that somewhere, somewhen there was life in outer space. I would define the "goldilocks" term for people unfamiliar, as the appropriate distance and orbit from a star, taking into account the different life-cycles and types of stars, for life as we know it to form on a planet. We've discovered several planets that fit into this category, and we know that all the elements present here that also helped life develop are common through out the universe. There is even a theory suspecting that the original single-celled organisms on this planet were actually frozen in an asteroid from some other ancient planet that crashed on earth billions of years ago and kick started life here; which is completely plausible. I have to say the odds and facts are with us on this argument. No we have never seen evidence of aliens (other than bacteria on mars, which renders this debate moot anyways), but neither have we developed the means to observe active, large alien life on other planets.

I can't say definitively that alien life exists outside of earth because we haven't found it yet, but I think it is unlikely that we are the only life in the universe.

There are a million stars and a million solar systems associated with them. It seems so Bizarre that only Earth houses life. Life must be somewhere, someplace.

While I agree that there is no substantial evidence to suggest there are indeed creatures like us outside of Earth (remains, visits, etc) logic can persuade you to believe the highly likely event that there are. It's very unlikely that we are the only creature of our kind, there are tons of solar systems out there, many who are probably all subject to evolution as we are. Thus, somewhere along the line, resulting in a far more advanced animal like we are, one that has what we consider "intelligence" and "consciousness" (my operational definition of that would be: An awareness of awareness, we are aware that we are aware/alert/thinking with an individual "I").