The only intellectually honest position to hold is agnosticism.
Depends what you mean by "agnosticism". When it comes to the question of belief, agnosticism doesn't answer the question. If I ask you if you believe the Panthers will make the playoffs next season, and you say, "I don't know and it cannot be known", you did not answer my question. I asked whether or not you believe it. If you do not say yes, you are necessarily saying no. Now, when it comes to KNOWLEDGE, agnosticism is better than gnosticism (speaking on religion here). If I ask you if you know whether or not the Panthers are going to make the playoffs next season, and you say, "I do not know", then you have answered my question by abstaining to answer on it. There is no way you can know either way on that, so the only honest thing you can say about what you know about it is nothing. Agnosticism and atheism are not mutually exclusive.
Words have meanings, and atheism is simply a lack of a belief in a god. It is not a position of certainty. I do not believe a god exists, but I do not know this to be certain. Might there be? Sure. Any good reason to BELIEVE there is? No. I honestly do not see how anybody can call that "irrational" or "nonintellectual". There is no good reason to believe in any god or gods. To claim knowledge of the existence or nonexistence of a god is absurd, because we don't know. Nobody does. If there was evidence in either direction, then that would be groundbreaking! There would be only one form of god belief, and that is the one that has proven itself to be true. However, this hasn't happened.