As a moderate rationalist, I believe that what happens to a human being when it dies is effectively the same that happened to it before it was born: Nothing. It does not exist, hence it does not perceive anything nor is it perceived by anyone nor does it affect anything within the system of the universe nor does it affect any other system that might exist. It's just not there or somewhere else. It does not exist. Circle of self-perception/self-imagination broken. The end.
Like Christianity, I believe that the human being has an eternal soul. Only my perspective is different: I think Christianity has the wrong concept of Heaven and God's will etc.. In my opinion, evolution itself (whether kicked off by God or not) will turn our very universe into Heaven! Not to forget: The human mind is not an outside observer of evolution but an active participator. Like Bill Hicks said: "I think it's time to evolve ideas." Eternal life might come biologically or it might be introduced by human technology. People will stop dying etc., so they will have eternal souls: Their bodies and minds. Unlike the existence Christianity believes in, this very merciful system allows to end the experience by means of death.
Death is a true miracle, everyone who feels that there must be something eternal about their lifes kind of have to agree with me. Problem is that death is currently mandantory, but I think this bug will be removed when evolution has completed its work. Death will stay as an option, but I guess no one would chose that option because who would shut off the camera when there's so much good stuff (and no bad stuff) to be experienced.
"Oh, I think humans need negative experiences every once in a while, otherwise they would not be humans. They would not know bad from good. They would not appreciate happiness." Bullshit. Whoever believes/preaches that suffering has to be an integral part of life needs to get their head examined.
I think that the human being ultimately has the capacity for good merely based on the *perception of beauty*. A smile of bliss and happiness is beautiful. A healthy and happy human is beautiful. It is a beautiful thing to experience to be happy about someone else's happiness. I think that this is ultimately what Love is, and I think it does not have to be beaten into the perceivers. Evolution is still underway. When it's done, Love will be default and the dark times will be but a weird memory.