There seems to be a long-running disagreement regarding the ideal attitude that atheists should have towards religious believers. One description I have seen of this dispute is the phrase "accommodationism versus assertiveness", although I've seen it phrased in other ways less even-handed.
I'd like to offer another prism through which to view this question. I don't claim it to be the only prism to use, or even the best; I offer it as a means of stimulating thought on the question.
Having embraced atheism for five decades now, I have had the opportunity to subject it to a wide variety of challenges, questions, and refinements. As a result, I have developed such confidence in my belief that I'm quite easygoing about it. I see no reason to argue with others about religion; let them believe as they will.
My mother taught me to recite "Sticks and stones may break my bones but words will never harm me." It never really worked, because words DID hurt my feelings. Only recently have my studies of cognitive science allowed me to realize that, inside the human mind, words really do influence our perception of reality. For the first 50 years of my life, I found it difficult to dismiss hurtful things said to me. Now, however, I have advanced to a level of senility that permits me to let such things roll off my back.
I suggest, therefore, that atheist accommodationism arises from confidence in one's beliefs, and that the confrontational approach reflects some insecurity about one's beliefs. I realize that this characterization of the issue steps on the toes of those who engage in confrontational behavior, and so I'm happy to entertain objections. I do ask, however, that such people not engage in confrontational behavior with ME!
My own approach to religious believers (people infected by one or another strain of that "mind virus" that once had much more adaptive function) is often "live and let live", but likely to be less so if they're seriously confrontational with me. I've realized that engaging a street preacher is more for the benefit of his/her audience.
(A good example of believers' contrasting approaches is in "Praise Cheeses" at notalwaysright.com.)
BTW, Dr. Kellie mentioned a great way to scare off door-to-door missionaries: "what boobs are good for".
In casual engagements with theists, I can let things slide, though not much. I've gotten away from online discussions because they mostly go nowhere and are ultimately a waste of time. Those arguing for their belief have no idea of who I am or what I'm about, and their accusations of hedonism or inherent sadness of my life or that of atheists in general are laughable. In the real world, I should mention that I've had JWs at my door three times in the past three years. Our encounters have been convivial with no hint of hostility, and their feeble arguments are easily parried. Mostly, they recognize they will win no inroads with me and quit while they're NOT ahead.
However, when theists attempt to make incursions into government, when they want to push creationism in schools or prohibit a woman's right to choose or attempt to superimpose their beliefs on a secular government, I will be assertive as all hell and I won't apologize after. I see the issue of christian influence on civil government to be a serious issue which deserves an equally serious response. My state and federal representatives have heard from me on such issues more than once, and so long as believers wish to turn the government to their favor, I will bust my ass to see to it that they never know success.
From where I sit, accommodationism may have it's place, but it's not much of a place, and it has none at all when the actions of theists have the potential of having a direct and untoward impact on me and mine.
Oh, yes, my use of "accommodationism" refers only to the people, not their actions. I'm happy to live and let live with any believer. But when they try to impose their beliefs on me, or inject their beliefs into the public discussion, I am fully confrontational
I agree with Loren. I only wish I could simply adopt a "live and let live" attitude towards theists, whereby my tolerance is predicated on being left alone by them. However, belief systems aren't held in a vacuum, and unfortunately they leak into many things that affect my life as well. As such, when my beliefs or values are placed in awkward positions by theists (whether directly or indirectly), I always feel the need to stand my ground.