As a declared atheist for the past 30 years, I know the difficulties of conversing with Unwashed, and must commend you on the skill with which you assay the task. I myself have found it an unrewarding endeavor and have since given it up. It is futile to debate with people who are under the impression that conceding a point is tantamount to eternal damnation.
It is important, I feel, if you are going to continue your discourse with the Believer, to stress that atheism doesn’t carry with it any obligation whatever to behave in certain ways, or espouse any ancillary beliefs; atheism is atheism, and nothing more. For example, atheism does not necessarily imply the acceptance of the theory of evolution (though it often does, and with good reason), the embracing or rejection of any moral code, tolerance or intolerance of any other group of humans, or even a rational mindset. Despite accusations to the contrary, pure atheism requires no faith whatsoever and makes no claims. Purest atheism does not say “God does not exist,” it says “I do not believe in God.”
Making atheism out to be anything other than what it actually is gives Believers an excuse to do the same.
I agree that, sometimes, trying to debate these topics feels like trying to push a chocolate cake into a brick wall. I’ve found that, at least for me, effectiveness requires a huge amount of time, tolerance, and patience – things that are often unavailable in the context of a religious discussion.
I agree that atheism does not necessarily carry with it moral or scientific baggage, and I also would not say, “God does not exist.” However, I espouse a method of philosophical thought more than I espouse atheism, and that method of thought has led me to a philosophy that I’ll call “Good Atheism.” Good Atheism encompasses both a lack of belief in deities and a desire to be philosophically consistent, which implies a number of moral rules. These aren’t the “faux Ten Commandment” rules I list on my Web site (those are intended as more of a joke than anything), but I can go into detail if anyone is interested. Frequent readers of this blog won’t find any surprises.