My, my, things exploded in here while I was trying to get some sleep. Serves me right.
I actually am a huge fan of science fiction (though I lean to the older school, of Clarke and Asimov and the like) and really enjoy authors' different takes on first contacts. But what makes good fiction are characters that one can relate to, hence why alien species are portrayed in some way anthropomorphized.
We would send scientists, diplomats, and explorers out to search for intelligent life. It is a very human thing to do. But human, extraterrestrials would not be.
Now of course, saying that they'd run off with our water/metals/radioactive elements/delicious bacon is also anthropomorphizing a bit, as it's what we do whenever we encounter a new place: build, extract, rinse, repeat. And that's a trap we all fall into: thinking aliens would do as we do, and have the same motives (survival/expansion as starters, though those are highly likely to be shared, as that's what life does, and neither bodes well for us).
Ignoring us is probably just as, if not more likely. We may be a minor, uninteresting species for something that can travel interstellar distances. Though, the resource idea is given credence when you think about the most likely form of interstellar travel: not "lightspeed" or any other unlikely, super fast motion, but generational vessels, "self-sustaining" mini-worlds. Which might still need to stock up on basics, and hey, look, that solar system has a nice planet full of readily available liquid water/carbon based squishies. Time to make up some more -Alien food substances- and +Alien entertainment devices+, and convert it over to a lovely colony world, because earth-like planets aren't that common (even just talking surface temperature). Let's face it, if they view us as competitors, we're sunk. And the idea that they'd let us live because "Yay, other "intelligent" life-forms, aren't they cute/precious" is so delightfully human. We like being something that matters.
What makes it so hard to predict an alien's actions is that they would be utterly alien. No similar cultural roots, no common thought patterns, no basis of understanding that is common other than possibly mathematics/chemistry. Which makes saying "we come in peace" or "welcome, please don't eat us" a little difficult. Or "Hey we're an intelligent species too, please believe us. Also, your acid sweat keeps melting our diplomats."
In the end however:
Though it is reasonable to say that there exists life other than us in this particular universe, possibly within our own galaxy, it may not be (and is unlikely to be) complex. Additionally, the likelihood of us bumping into another "us" is tiny given the vast distances of space, even if they do exist.