I think it probably is an issue of semantics, jason. There is, i think, a perception that agnosticism = open minded scepticism, whereas atheism = rejection of any god, a dogmatic response.I would disagree with this perception, but I would certainly agree that people exhibit differing certainties of belief, from zealous theist to strong atheist.
The definition of atheism is simply a disbelief in gods, and I have not met an atheist yet who says categorically that they could not be persuaded by the right kind of empirical evidence.
There is a kind of sliding scale though - the first time I saw it, it was Dawkins who suggested that theistic belief went through a spectrum of zealous belief in God, a sort of fundamentalist faith, all the way to a complete rejection of any kind of deity, with agnosticism sort of in the middle.
For myself, I would say I am at the strong atheist end of the spectrum - but- I follow evidence, and could be persuaded to change my mind, given sufficiently strong, repeatable empirical evidence.
Personally, I think the description of oneself as an agnostic atheist, or as an agnostic is a bit of a cop-out - its a compromise position, with an intent not to offend - at least, thats the way I see it ;)
If you do not believe in gods, you are an atheist. You shouldnt feel the requirement to temper the perception by calling yourself an agnostic, instead