I would say atheism is no more a religion than theism.  A religion is a "world-view" with respect to all the most pressing unscientific questions concerning the human condition.  Questions such as "what is the meaning or purpose of *my* life?" and "what does it mean to be a good person?" and "what is the best way to raise my kids?"  The scientific/objective answers to these questions are rather shallow and, certainly, for most people, unsatisfying, but that doesn't mean that the supernatural/superstitous "answers" are any better.