It's hard to tell sometimes what someone believes in. With the internet, the phone, or any kind of mail, we don't have to actually see people very often, thus become less attached to them and their lives. Unless a topic is volunteered, it never comes up and you never know about it. A friend of yours online might be the exact opposite of what they appear to be online, and you would never suspect a thing because you don't actually see them.
Even if you know what someone is labeled as, that doesn't mean you know what they believe. So what if you are calling yourself a Christian. Does that mean you believe your children should be stoned to death if they put even one foot out of line? Of course not! So the label doesn't provide all of your beliefs. Similarly, not all Atheists believe everything that science tells them, that's just how people interpret the label placed on them.
So, the question I'm building up to is,
“What do Atheists believe?”
This is a difficult question to answer, as all Atheists are different. The best way is to first explain what an Atheist is.
An Atheist is a person that is without a belief in any kind of god or deity.
So, I suppose the more proper question would be what don't Atheists believe in. It is universally accepted by Atheists that no proof of a higher power exists, however, not all Atheists think the same way on other topics. There are some that do not believe in evolution, some that think scientists are conspirators, some that are complete anarchists, and some are even Buddhists.
There are some people who become Atheists for entirely the wrong reasons. For example, there is a very sick person that they are close to that is dying. They pray to their god and nothing happens, the person dies. Suddenly this person decides there must be no god because their prayer wasn't answered. This is a bad reason to become Atheist as an Atheist must be skeptical of gods, not completely denounce them. One quick word from a friend and this person could be theistic again without any harm done to their religious position. The most commonly accepted manner of becoming an Atheist is when someone doesn't see any proof of their god existing, but there are other types.
The only common belief that all Atheists have is that there is no proof of any god or deity, as that is the definition of Atheism, a lack of belief in deities rather than a belief against them. This is why not all Atheists get along and why almost every religion has an instant disposition about them.
In short, we all have come to the conclusion that no proof of any god exists at this point in time, but are open to being proven wrong. Everything else is up in the air.