Responding To Anti-Atheist Bigotry: Offense or Defense?

When I encounter bigotry, I often feel obliged to speak out. I feel this way not just in the case of anti-atheist bigotry but also in cases of racism, gay bashing, sexism, and the like. I suppose it is the realization that by remaining silent, I am implicitly condoning the behavior that motivates me to speak out. Still, I'm not always sure how best to respond in these situations. This recently started me thinking about the way the secular community should respond to bigotry directed at us.

When confronted with anti-atheist bigotry, what is the atheist to do? Since I have rejected silence as an option, this leaves me with the need to respond, but what sort of response is optimal?

I realize that what I am about to say is a gross oversimplification and that the choice of how to respond will depend greatly on the specifics of the situation, but I believe this may provide a tentative starting point. It seems to me that responses can be primarily offensive (in the sense of going on the attack) or defensive in nature. An offensive response might involve moving past the insult to criticize religion. On the other hand, a defensive response would involve an attempt to correct the misconceptions inherent in the insult, educating the bigot about atheism, etc. As an illustrative example, consider the following conversation between two Christians (after all, Christians are not exactly known for their tolerance):
Christian #1: "There go those stupid atheists again, whining about Christmas. Can't they understand that America is a Christian nation? If they don't like it, they should just leave."

Christian #2: "Yeah, I think they are just depressed this time of year. Think about it - without god's love, they must be miserable. I'm surprised they aren't all suicidal this time of year!"
An offensive response would make no attempt to clear up the many misconceptions evident here but would focus on the idiocy of the speakers' belief system.
"Stupid atheists, huh? It sounds like you are the ones ignorant of American history here. This country was founded as a secular democracy. In fact, the founders explicitly rejected the whole Christian nation garbage! And if you really want to talk about being miserable, let's look at this god you actually worship for a minute..."
The tone of the response is not what I'm trying to highlight as much as the focus. This responder is making no attempt to defend a position but directly attacking that of the speakers. A defensive response might look something like this:
"This just shows how little you know about atheists. We don't believe in any sort of gods, so why would we be depressed over them? You probably don't spend much time being sad that unicorns might not like you, right? Many of us are just as happy as you are this time of year. We get some time off work and get to spend it with our families."
This response is more concerned with setting the record straight with regard to atheism than with criticizing what the speakers believe.

In my opinion, believers have come to expect the defensive response from us because it is usually the one they receive. Many of us feel more comfortable with this sort of response. It may strike us as being more polite, more socially acceptable, or even more rational. We might even justify it by telling ourselves that we are refraining from sinking to their level. But defensive responding, especially when it becomes our habitual method of responding, comes at a cost. By falling into the cycle of theist attacks - atheist defends, are we not complicit with the theist in assuring that atheism rather than theism is the subject of criticism?

Perhaps we should strive for a more balanced approach by increasing the proportion of offensive to defensive responses. The last thing we want to do is foster the already prevalent view that religious belief is somehow exempt from criticism. Atheism, once one understands what it is and what it is not, needs no defense. On the other hand, faith-based belief is simply indefensible.