You can be agnostic and an atheist at the same time.
I think that both theists and atheists are agnostics, because we don't *know* whether God exists or not, as agnosticism deals with knowledge. Some people just believe in Him while others don't.
Also, I think it depends on what you think about that "unknown force" that created the universe:
If you believe that it was (possibly) God, but you don't believe in religion, then you're a deist. If you believe that it was a just a mindless, natural force - or something like energy and matter - then you're an atheist.
I think that both theists and atheists are agnostics, because we don't *know* whether God exists or not, as agnosticism deals with knowledge. Some people just believe in Him while others don't.
Also, I think it depends on what you think about that "unknown force" that created the universe:
If you believe that it was (possibly) God, but you don't believe in religion, then you're a deist. If you believe that it was a just a mindless, natural force - or something like energy and matter - then you're an atheist.