The main problem with identifying as an atheist is that the word doesn't really have an independent identity. It literally means "not theist," but that seems a rather limiting description. I don't believe in unicorns, gnomes, elves, fairies (including the Tooth Fairy), the Easter bunny, Santa Claus, widespread alien abduction or alien visitation, psychic powers, or ghosts either, but I don't use those to define my belief system, and it seems pretty silly to suggest that I should.
I am perhaps more accurately a skeptic, wherein I don't believe in anything without some very good reason to do so. Start with the least number of assumptions possible and work from there. It's perhaps difficult to create a larger assumption than "assume god exists," so at least "atheist" gets that out of the way early. "Skeptic" is also mostly just a broader negative term though, mostly defined by not believing all of the things that people believe.
I would perhaps identify as a secular humanist, although that's rather a mouthful, and I can pretty much guarantee that 99% of the population wouldn't understand what I meant. At least I can be pretty sure that "atheist" will generally get the idea across, even though there will likely also be a massive misunderstanding of what I mean.
The word "atheist" does have some fairly negative connotations surrounding it. Partially this comes from the perception that, if you're not worshiping god, you are by default a satanist. There are also a large number of people who seem to believe that, were god not watching their every move, they would instantly transform into thieving, murdering and raping lunatics. I'm not sure if these people are just extremely cynical or if they have severe emotional problems, but if that sort of stuff is commonly bubbling under the surface in the ultra-religious, we should probably be Very Concerned Indeed.
Most of those negative connotations arise precisely because "atheism" is defined in terms that deny a specific thing. "Realist" is a term I hear thrown about, and while I think that is perhaps a reasonable term, it doesn't really supply any obvious tools for determining reality, which is really the whole problem.
I realized some time ago that doubt is the path to truth. Between the hard lines of "belief" and "not belief" there is a vast chasm of, "maybe, maybe not, let's gather evidence and information until we can be more certain." I drive people utterly insane with my default answer to most questions, which is, "I don't know." But when I really don't have good information (or often no information at all) I don't know what they expect me to say. I can make a wild, random guess as good as anyone, and sometimes that's good, but it's not reasonable or rational.
So what do I believe in? I believe that evidence, logic and reason will steer us in the right direction.