I must admit, one of the more amusing arguments from 'believers' is that "anyone who thinks we are alone in the Universe is a fool".
I don't think we are alone in the Universe, but like Arthur C Clarke and Carl Sagan, I just don't think they'd have any interest in coming here, and even if there were scientific missions coming to Earth they would have to be phenomenally incompetent to place huge banks of glowing lights on vessels that are trying to remain hidden 
i have an easier time believing in the existence of aliens, but i have a really hard time believing that aliens have figured out how to pull off ftl travel. i kinda figure all travel will be done with generation ships. or perhaps use cryogenics. aliens may have anatomy that allows them to be frozen without damage, like certain frogs and insects which can survive winter freezing. an intelligent species may have these traits, or at least a firm understanding of biological engineering. perhaps they can extend their life span to survive a 100+ year trip from system to system and back. the question of course is why. science can be done with robots, as can scouting for candidate planets for colonization. and if i was an alien sending ships to scout a planet, i certainly wouldn't put big glowey lights on them and make them zigzag through the atmospheres of planets with intelligent life, especially if you intended to move in on such intelligent life. they would send mostly hard to spot hardware similar to our spy satellites, with passive sensors, which we would likely mistake for small space debris.
Consider that they might simply live long enough for the 10-year flight to seem like a blink of an eye, or be able to naturally hibernate, assuming this concept would even apply to them. Space travel could be perfectly natural and pretty easy to them, sort of like flying an airplane for humans. It's unreasonable to expect human problems with space travel would apply to aliens.
IMHO, the most realistic approach to aliens distances itself from
everything that makes aliens resemble humans. They'll be from a different planet, evolved in different conditions and most likely only fit the most basic definition of life. They might be able to use tools, and have their own kind of intelligence, but concept such as "civilization" or "technology" as understood by humans might be completely alien to them, just like their concepts to us. Stanislaw Lem did it really well in Solaris, and in Master's Voice he explores a very realistic (though a bit depressing) approach to the first contact. The Ocean in Solaris is really alien and it tries to establish some sort of communication with humans in a way it's familiar with (at least, that how I understood it), and the humans try to communicate with using their own ways. The result?
A bunch of insane scientists and a library of rather useless books about Solaris on the Human side and a... reaction on the Ocean's side, with we can't even understand.