If any of you haven\'t read the series \'maniforld\' by Baxter... if you are into theories like the one two above.. you would love that book. It\'s one of my Favorites...
I do believe in Aliens, simply because of the numbers of stars in our galaxy alone... I figure there are hundreds, maybe thousands, of other sentient species in the milky way, and of those species, at least a few must have survived long enough and under the right conditions to have expanded technologically to the point that they can travel between stars.
As to what they would be like if/when they ever arrived here? Well, they would have evolved completely differently from us. Who knows how their social structure would be. As such, I can imagine any number of likely scenarios... study, peacefull contact, resource plunder, or just \'letting us alone\'.