Heaven, hell, and the afterlife

[revots33]

This is particularly for the theists, although I'd like to hear any opinions.

Do you believe in heaven and hell (or some other version of eternal life after death)? Why or why not?

The reason I ask is this. There's been a lot of discussion about why people do/don't believe in God. Many believers see God as the "first cause", from which the universe must have come. Others argue that the complexity of the universe shows purpose, and so must have been designed by a supreme being. There are other philosophical arguments as well, and I think a lot of them have validity.

But I haven't heard many arguments for belief in the existence of heaven or hell. Since this belief cannot be argued in the same way the existence of a Creator can, I'm curious as to what reasons people might have for this belief.

So, why do you believe/not believe in heaven and hell?

And, if there was some hypothetical way to prove, beyond any doubt, that we simply cease to exist at death, and that heaven, hell and the afterlife do not exist - would that knowledge make you stop believing in God? In other words, how much is religious faith connected to the belief in some form of eternal life after we die?