I agree with what the other posters said. I think funnyderek gave a very good and concise explanation. There is a rather prominent atheist that deals largely with muslem issues named Ibn Warraq - http://www.challenging-islam.org/articles/warraq-debate-muslims.htm
could Buddists be considered Athiest?
There are indeed many atheists that are also Buddhists. I think even Sam Harris is. If he doesn't consider himself such, he has at least adopted a great many of their practices and speaks very highly of their philosophy.