Variations of this topic have been around JREF/ISF for as long as the forum has existed, and will keep coming around because there are always some people who have not yet thought it all the way through. I usually avoid this topic, because I have thought it all the way through (at least, no one has come up with anything I haven't considered about the topic in a very long time), but I've decided to throw in my two cents this time. I want to add something to the topic from slightly different angles than I often see it discussed. It's not deep thought and you won't be enlightened, but depending on exactly what you have thought about in the past, it might be something slightly different. I hope that it's at least mildly thought provoking for a few.
First, I sometimes call myself an atheist and sometimes an agnostic. It of depends on context. The key difference between the two is that an atheist is extremely confident that there is no God, while an agnostic doesn't actually believe in God, but doesn't rule out the possibility. I find that when it comes to specific religions, I'm an atheist.
For example, if I know I am talking to a Christian, and the Christian asks me if I am an atheist, I generally say that I am. The reason I do this is that, with respect to Christianity, I'm an atheist. I am very, very, confident that the Son of God did not become incarnate in the form of a Jewish rabble-rouser. The possibility that I am wrong about this is, in my opinion, not even worth considering. If I said I am agnostic, that could be taken as I am uncertain, and that I don't believe that Jesus is God, but I'm open to the idea.
In general, I'm pretty darned confident that there is no "personal God". i.e. there is no God that listens to prayers and intervenes in human affairs. With respect to a personal God, I would say I am an atheist.
On the other hand, I am open to the idea that the universe could be the product of a conscious mind. I don't see any evidence of that, but I have no other explanation of its existence, and I don't know what the evidence would look like if it were there. It's the old question "why is there something instead of nothing". I have no explanation, so I'm open to the idea that somehow, a conscious decision was at work. (Of course, that demands the question of why that consciousness exists, and that too cannot be answered. Really, this is all pretty well worn ground.)
So, with respect to a general concept of a God, I don't reject the possibility out of hand. I just don't happen to believe it. That makes me an agnostic.
My general attitude toward God goes along with, and has been influenced by, the teaching of the Buddha on that subject. The short version of that topic is that when someone asked the Buddha if there were a God, he pointed out that God, if he exists, would have an infinite mind, and that no man, with a finite mind, could possibly understand such an entity. Not only could you never know what such an entity would want, you couldn't even truly understand what it would mean for such an entity to exist. Therefore, the question doesn't matter, and you should ignore it an live your life in the best way possible.
I would say that the Buddha was an agnostic, not an atheist.