For example, I'm an Agnostic-Atheist, in the sense that I don't believe in a God, making me an atheist, but I also accept that I can't know there is no god, therefore I'm an agnostic. I try to assure people that I'm willing to be convinced other wise on the God question, if a valid argument could be presented to me.
Here's a short list that should clear this up for some of you people.
Theism: Belief that God(s) exist.
> Gnostic Theist= I KNOW there is a God.
> Agnostic Theist= I don't know there is a God, but I believe there is one.
Atheism: Disbelief in God(s) Existence.
> Gnostic Atheist= I KNOW there is no God.
> Agnostic Atheist= I don't know that there is no God, but I don't believe one exists.