In my mind, atheism has always meant "No God" and agnosticism always meant, "maybe, not sure either way."
This new age type of thinking by the new atheists trying to redefine atheism as "agnostic atheism" is poorly constructed in my opinion.
Sure you may say, "I don't see any evidence for God so I'm not going to believe there is one." But, this is not atheism. Atheism specifically says "No God." Plus, you run into problems with this mindset because we didn't discover black holes until recently. So, was someone justified in thinking black holes didn't exist until we found the evidence?
The minutiae of labels has little value. That I am unfortunate enough to live on a planet where many people claim many gods means that I'm forced in to taking a stand against their nonsense. I consider myself an atheist, though I sometimes question whether or not the Sulu high god Unkulunkulu may in fact be real. So in that case, I'm willing to call myself an agnostic. But on average, I'm an atheist.
But whatever we humans think/believe/accept, the first thing we have to accept is that we are not likely right about many things. Religion or otherwise. If a few people get blindsided every time there is a new discovery in science, so be it. Thats what folks get for being positive about unknowns. People have been wrong since the beginning of humanity, and they will continue to bat less than 1000% until the last person dies. Each of us has to make up the world because none of us has enough information to be sure that we are right about anything.
However, it is often easy to tell when someone else is wrong. People who say that the earth is flat or that kids shouldn't be vaccinated or that capitalism is the best form of government ever and should never be challenged or changed, they are wrong. They base their conclusions on either false information or no information at all, and they have little business making factual proclamations when they don't value truth in any sense of the word. Ignorance, selfishness and fear are lousy teachers, and anyone who thinks that they have a PhD in life just because they just had a half-assed thought is automatically wrong. But sadly, it is impossible to tell such people that they have erred. They are too good at it to be corrected.
So if a person believes something and yet their beliefs don't seem to vie with reality ("I pray to jesus every day, but I still haven't won the lottery", or "People of other races are inherently inferior, so why is it my boss is of a different race and I'm just the janitor?"), they are doomed to draw errant conclusions at every turn.
However, in the case of scientific thoughts and discoveries, one can could have come to the conclusion that there are no black holes and later find out that they were wrong without ever having to delve in to the belief business. In that case, people look at available information, make conclusions, and accept that they might be wrong. Because they know that they might be. Now a layperson might reach similar conclusions, based on a show they saw on the Discovery Channel or something, and indeed come up with a belief about black holes or bigfoot or the Loch Ness monster and end up having their beliefs dashed by new information. But that doesn't count.
Because as a general rule, if a person hasn't used their brains to reach a conclusion, then it is a belief. And always subject to questioning. Sadly though, only by others.