I have to add to this topic, as I have very strong beliefs in the area concerning 'gods' and religion.
I find there are several reasons people believe in a god. They were brought up that up, they feel it gives them some direction in life, they want to go to heaven, peer pressure, etc.
If you were born into a religious family, you still have your own free will to make a conscious decision on whether you wish to follow their beliefs once you are an adolescent. The problems arise when you have been brainwashed from a young child into believed that there is no other possible way. Children are naive and innocent and they can be forced down certain paths with relative ease. This isn't fair and is preying on their innocence.
Take a look at this, it doesn't just happen in Islam, as a lot of people portray it to:
I also don't feel that I need to have a religion to give my life a direction or reason. I am a happy, well rounded individual. Why would I need a 'belief' to guide my direction?
With regards to going to heaven - how many religions are there out there? If I were to follow one religion, if that religion is false, would that deny me access to heaven?
How about thinking of it this way:
If there is a god, and he is good, as long as I live my life to the best of my ability and do not do wrong to others, I should be on track for getting into heaven.
If there is a god, and he is bad, shunning all others from any other religion than his own, a lot of people are going to be screwed over getting into heaven.
If there is no god, we all just die. Harsh, but true.
I see no direct evidence of god existing, therefore I do not think there is a god. It's not that I don't "believe" in god, I just don't think he exists in the first place.
You can't use the argument of "But look how complex and intricate our eyes are, how amazing all the systems that keep us ticking are, etc etc, a god MUST have created us because there's no other way it could have happened". When I ask religious people why they think god created us, they answer with something like that. Or "because it says so in *whatever book*". Sorry, I don't buy it. Circular reasoning is not a valid argument.
Cause and effect reasons are absolute balls to. "I prayed for him to be cured of cancer and then he was!" Ok, so how do you know he was cured BECAUSE you prayed? "Because I prayed then he got better..." Not a good enough reason. If I were to have a headache, take an ibuprofen and also pray for it stop, then it did, what stopped my headache? The ibuprofen, or the prayer. How about I don't take the ibuprofen, what caused the headache to go away? Was it the prayer? How can you PROVE it was the prayer? Exactly, the entirety of religion relies on blind faith and guesswork, not true facts.
That is why the worldwide numbers of those following a religion in educated countries is diminishing. In the USA alone, atheist numbers almost doubled in the last 10 years or so I think. It's mainly due to the education system nowadays. People are taught that, in science for example, to provide adequate explanation for something, there must be evidence and a reason. Kids just aren't seeing that in religion nowadays, they are asking their own questions which inevitably results in some of them turning away from faith and religion.