I'm not going to comment on the
However, my opinion of extra-terrestrial life is this:
It would be extraordinary for us to assume that we are alone in the universe. The fact that complex organic molecules form in nebulae from the ionising radiation of newborn stars, and that organic residue is likely to help form any planets that orbit those stars, then the ingredients for life are strewn throughout the known and observable universe. (In a recent journal article, it has also been shown that DNA precursors form in these nebulae, molecules that form helices and are self-replicating, so life is found, in it's constituent parts, where star-birth is observed).
Not every planet around every star will harbour the necessary conditions for life to evolve, however, in the observable universe, there may be billions of planets that have the right conditions for life to emerge. it may be only bacteria; it may form into complex life like ourselves - intelligent and technological.
Taking these factors into account, the evolutionary processes on an alien world would be very different from the ones here on Earth, so the chances of any alien life being similar to us is, whilst not impossible, highly improbable. We evolved from earlier, simpler animals - they would do the same, but their progenitors would face different evolutionary challenges and would evolve along different lines.
The chances of one of the life forms being intelligent enough to develop space travel is reasonably good (assuming they don't wipe themselves out in war or other disaster). However, the vast distances between the stars, even in our own galaxy makes interstellar travel highly improbable - even at the speed of light (the theoretical speed limit of the universe), it would take 4 years to reach our nearest stellar companion. Our galaxy is around 100,000 light years wide, making a quick visit to a stellar neighbour a multi-generational trip. Even assuming that aliens might have longer lifespans, would you really want to spend centuries in a spaceship to visit another world that you don't even then make proper contact with?
Whilst I believe that finding alien life nearby (Mars, Europa, Encedalus) is almost inevitable, and finding evidence of alien life on another world is also inevitable (via indirect means, such as spectroscopy), the chances of us being visited by aliens is highly improbable, due to the inherent speed limit of the universe, the power required to drive such a means of propulsion, the time it would take to get here, the lifespans and boredom threshold of any alien species and the mechanics of eating (where would you store all the food for a centuries long trip on such small craft?).
Whilst it is a romantic notion that we are being visited by alien craft on a regular basis, the mechanics of such visits are highly improbable and the sightings usually conform to our (human) cultural norms (and tend to evolve over time - the aliens from 50 years ago do not resemble the aliens of today, neither do their craft).
To sum up:
Alien life - very probable
Alien life visiting us - very improbable