this helpful diagram (see above) from Atheist Revolution explains the differences between being atheist and being agnostic, which very many people confuse (and conflate).
Using the above chart I would describe myself as as an Agnostic Atheist, which I usually just shorten to "atheist" since that is what most people understand. I most definitely do not believe any god exists, but I don't claim to know that no god exists. However, I think the preponderance of the evidence (i.e. there is no credible evidence that god exists) and simple logic (Occam's Razor) should suffice to allow one to come to the conclusion that god does not exist.
What do you think?