For me, I find that letting potential dates know about my atheism as soon as possible is a good thing.  It weeds out all the people who would list themselves as "spiritual but not religious" who would get offended that I don't condone their lack of intestinal fortitude.

Then again, I'm an atheist activist, and couldn't possibly date a theist.  In general, however, I strongly recommend against atheists dating theists.  Dating tends to lead to fucking, and fucking has led to quite a few babies in the past.  When people who disagree about religion make babies, it's usually bad for the baby and the parents.

To answer your question directly, it depends on how bad you want a date, and whether you're looking for a screw or a long term girlfriend/boyfriend.  If you're just looking for something casual, you're probably better off just listing yourself as "prefer not to say" or "I'm not religious" or whatever non-threatening noncommittal response they give.  Don't put "spiritual but not religious" unless you really are.  You'll piss off a lot of girls that way.  If you're looking for the love of your life, or at least the next few years, go ahead and put atheist.  You're not doing anybody any favors by finding someone who's less than what you're looking for.

Having been born and raised in the deep south, I have always considered religion a big deal. I have no desire to try forming a relationship with someone only to discover that we are going to argue over something repeatedly and heatedly. Knowing myself, we will argue about it. I had rather wish her a good night on the first date and never see her again rather than try to build a relationship while either tip-toeing around a subject or loudly clashing over it. I've seen firsthand how passionate, and violent, some people can be regarding their religion. I prefer my life to be mostly drama free. Along with if they have or want children ( I don't ), their religious beliefs are among the first things I enquire about.

I'm also not sure that this religious value is only a product of the south, either. My wife is atheist, but was raised in an Orthodox Jewish family from New York.  Her sisters and cousins wouldn't even date non Jews, let alone consider marrying one. Even their friends are Jewish, and they too won't date or marry non Jews. Most of the Catholics I've met across the country won't date non Catholics either. So for a lot of people, not only does your belief matter, but apparently so does the flavor of your belief.

I can't decide whether to laugh or wince, so I'm doing both! Looks sort of like a seizure in the reflection of the screen.

That reminds me of a line from M*A*S*H.  I wish I could remember it exactly, but I think it's Igor who says something about having a beautiful girlfriend waiting for him back home... and also his wife.

It's better to admit to it and add to it that you refuse to date anyone who has an imaginary friend.

                        Good one !

Personally I have found that it depends on the individual. Some of the most intellectually fulfilling relationships I've had have been with theists. The distinction being that the women concerned were able to argue about religion without emotion getting in the way. i.e. without shouting & getting angry.

People of either sex with that disposition are sadly few & far between though. 

And Hamby's got it right. If you're looking for something long-term and meaningful, don't bullshit.

That sounds hawt!

      If your haveing SEX then go with  A, what else are your thinking about!!!!   If she grabs a Giddeon and keeps on preaching afterwards;  then do her again; think!!! She can bring all the imaginary friends she wants as long as the sex is real.

I would put it on the ad, so there's no massive surprises on the date. It might lower the number of responses you get, but should at least increase the quality of them.

Of course, I am a stringent atheist. I wouldn't accept going to church or baptisms or such, and wouldn't couple with anyone who desires such. Those who are less of a stickler than myself might do well enough just by saying agnostic or spiritual or something.

I went around dating people for awhile before I settled into monogamy, and I was very, very, VERY up front about my athism in online dating profile and such.

On Okcupid, I got about 20 e-mails a day.

Than again, I'm a woman. I realize that single, attractive, vehemently atheist women are goddesses, especially in the online world.

I ended up attracting other atheists, or people who said, "I'm not atheist, but you're cool!" and etc. The guy I settled down with and I talk about religion 50-60% of the time. It works out well.