well as I conceive it the line is that the atheist denies the existence of god (hardline) or denies that the belief in god is rationally justified (softline) while the agnost suspends judgment on the matter and simply says god may or may not exist while the believer ofcourse says God exists.

im not sure how far you have to leave the door open in order to go from atheist to agnost, but if there is a thin line between them i think your position is on it.