I agree with mavie, thiesm is the belief in god, atheism is the lack of a belief in god.
Only people who have either never heard of god, or have never done any research should be called agnostic.
So if someone says: "Do you believe in god?" What do you say?
And if someone says: "Do you believe in fairies?" What do you say?
You can't prove one way or another about either one... but if don't believe that they do exist, then you are atheistic about them.
But if someone says: "Do you believe in Ninko-Tonimaticons?" What do you say?
Well if you have no idea what the heck a Ninko-Tonimaticon is, then you are agnostic in regards to them.
So you can go around calling yourself agnostic, but in my opinion, since you are educated on the subject, you are an atheist unless you think god exists. No offence though. I'm an atheist, because I do not think god exists. I can't prove it anymore than I can prove that fairies don't exist... but I'm still an atheist.
Summary, there are three classes:
I believe in god. _ Theist.
I don't believe in god. _ Atheist.
What's a god? _ Agnostic.
And those titles aren't etched in stone, you are allowed to change your mind whenever you need to. You can be a theist and say "I think god exists, but I'm not sure." Likewise you can be an atheist and say "I don't think god exists but I'm not sure."
You don't have to have undeniable proof that your right before you assume a title... in fact being able to question your beliefs simply means your open minded, and not an idiot... not that you can't say one way or the other.
Allow me to illustrate. (Caution, watchtower style illustration.) Do you vote for a president? Are you 100% sure that the guy you vote for is better than his opponent? Or will you able to change your mind if evidence to the contary comes up? I'm sure you wouldn't refuse to vote just because someday you might change your mind... Belief in god is the same, plus you are allowed to change your mind later on.
LtCmd.Lore