No, everybody is deep in his heart a believer. Not necessarily belief into some specific religious stuff or in God but at least belief in the importance of his own life.Everybody is an agnostic, and if they say otherwise they are lying.
Now whether you are an agnostic atheist or an agnostic theist is a whole 'nother thing...
Freud, a textbook atheist if there ever was one, had to believe that his life's work is immortal (hence his obsession with finding a suitable "son" and the conflict with Jung). It doesn't have to be work, it can also be children or paradoxically enough even death itself (martyrdom, finding a cause worth dying for) which is your immortality device. A hedonistic life cannot be a full life.