An atheist is still in a theist paradigm.
In describing yourself, when you use broad categorizations, such as I'm black or I'm white, or I'm a chemist or a I'm a physicist or I'm an electrician, or I'm an atheist or I'm agnostic or I'm religious or I'm Jewish, you are saying that the questions that these are answers to are important to you. They have meaning and value, and are worthwhile ways of categorizing yourself.
My idea is that we should be careful of the categorizations we have for ourselves. I, personally, am religious, so I give that question a lot of weight, but for someone who is atheist, or someone who doesn't tend to consider religious questions and such, it seems as though the question has little bearing, though there may be exceptions. It is not applicable in one's self concept. If you characterize yourself as an atheist, you are still in a theistic paradigm. So, my idea is to stop thinking of yourself as such.
While I am thinking particularly of this instance of religion, the idea has wider applications too. For example, in talking of one's skin colour. It is at times useful in helping to identify someone, but otherwise the distinction made between people with different skin tones is usually not an actually relevant question, not to say that heritage and ethnicity (important in the cultural differences and the genetic differences that are consistent across a particular group) aren't applicable.
My idea is mostly related to self concept though. To other who give value to those questions, it is entirely valid to answer them. Religion may not be important to you, but to your associates for which it is, you can still tell them that you are atheist, though if that was the case for me I'd say 'I do not adhere to any religion or believe in God', so as to still come from somewhat outside of that way of thinking.