Personally I think labels tend to shoehorn people into certain classes, and like you said Piaise the definitions are not always clear.
Some say there is no such thing as an agnostic, either they do believe in a god or they have not been convinced yet, making them an atheist by default - either you do believe or you don't.
Some also say there is no such thing as an atheist, and that atheists can't disprove that god exists - not the scientific measure of proof but then again that usually comes from a person who doesn't form beliefs based on scientific proof, and relies on faith instead.
Not to mention different opinins on what god "is". Is god an entity or a frame of mind? Is god a seperate entity or is he "everything"?