I like the answer that was given.
"Remember that coming out in your private life doesn't mean you have to come out at work. The workplace isn't an appropriate place for religion OR atheism. If they're constantly flaunting their Christianity, they're in the wrong, and you don't have to flaunt your atheism to counteract their gaffe. Keep your nose down at work, and do your job so well that nobody will think of giving you less than an excellent rating. Don't comment on religion one way or the other. But in your private life, don't be afraid to make non-believer friends, or to hang out with them in public. As long as you're not seen as an active threat to Christians at work, they're unlikely to cause you any trouble."
Good one...I'll use THAT one. If you say "I'm not a member of a church" you're likely to get INVITED. Personally, I just stay vague and neutral. The opposite of militant. I see no reason to get into this sort of thing in the workplace...I don't think the opportunity will even come up because I'm too busy pretending to be WORKING>ha.
I look at it like others have commented: Gossip. We don't need more gossip in the workplace. I have a hard enough time juggling all the drama (and work stress) on a day-to-day basis...I don't want to be ADDING to the drama.
But maybe I'm predicting that there would be some sort of huge reaction to my 'coming out at work'....maybe the response would be like crickets in the audience...'so what's the big deal'! ha If somebody asked me directly (and I cared about their opinion of me), I would give a direct answer: I don't believe in any gods. (I like the term 'freethinker' too, because it's vague and kind of new-agey sounding. Like I'm a hippy or something. That's a safe role to assume.)