I am strongly reminded by a passage in one of Kurt Vonnegut’s works of fiction. As I am not an encyclopedia, I must paraphrase:
An Alien visiting from another planet took it upon himself to figure out just what was wrong with Earth’s most popular religion; Christianity. He came to the conclusion that upon Jesus’ hanging, readers were obliged to think, at least on some level, “They sure picked the wrong person to hang”. This was inherently flawed in that it suggested there was a RIGHT person to hang.
The alien proceeded to re-write the bible making the proper adjustments, and the world largely lived happily ever after.
I apologize if anyone was offended by that blasphemy, but I believe it illustrates a relevant point. Although as Bruno so eloquently puts it, we cannot pinpoint such things as relevance.
However, Bruno, I think you made a small mistake. Atheism is not a faith in no god. It is a faith in no theology. The literal translation is without religion. Although the term has certainly been diluted.
I believe a better term for Muzzius would be ‘weak athiesm’, since he seems to believe in at least some of science.
And although your are right, strong athiest is a faith in the non-existance of god, weak athiesm is the assumption that we should believe what makes sense to us. This means science.
More in line with the original question; Most of what humans believe is delusion. Most people fail to realise that nothing we sense, by whatever manner, can be completely trusted. We could be hallucinating, we could be decieved, and more importantly there’s the possibility that we’re completely detached; that our minds exist but that everything around us, our reality, is a figment of our imagination. (See Philosophical basis of The Matrix)
Nihilism of more like denying everything for the time being, just until you cease to exist/are able to verify your reality. At least, this is my take. A blanket term seldom works properly, since people are so often so different.
On my computer(currently broken) I have a link to a wonderful article concerning the evolution of morality as separate from religion.
The only purpose served by religion in modern society is to fill a gap. I have never known an athiest who did not wish for something to answer their questions about the universe. And indeed, religion is the ultimate answer for it’s subscribers. People are angered by the argument that “God did it”, but this is the whole basis of religion, that God did indeed “do it”.
So, in my opinion, it is most likely delusion. However it is also empowerment in that it gives one the power to be happy. The French philosopher Bruno mentioned is a wonderful example.
In the dark ages, religion was used as a weapon, because of it’s flaws. But in this age, science has forced most people to rethink their religion, at least to he point of reading the spirit, not the letter, of the Good Book.
Disclaimer: Capitalization of words such as “God”, “Jesus”, and “Good Book” are signs of respect for english grammar, not signs of personal belief.
No need to be aggressive! 
As Antonio said, the word atheism traces back to 
I myself dismiss the rigour of science, for as far as I’m concerned it makes science no better than religion in telling us the "what"s and the "why"s. I do think science might be useful at times telling us the "how"s, though, but it’s only there to be used pragmatically; to me, giving sense to life through science (or through religion even) without giving it at least a second thought is just missing a big point.
