The soul leaves the body and the body turns to dust. I believe that we meet up with our friends and relations and feel no pain.

Another form of life. But nothing to do with god or religion. Maybe another life like this one, where you are reborn as someone else on this planet, shortly after you died. Or maybe life as a strange creature in another dimension =). And if not this, than I guess nothing, void. Which wouldn't be bad, since you you wouldn't be there to feel sad about it.

decomposition. your matter & energy are recycled by other living things. Eventually the Earth is sucked into a black hole and all the black holes eventually suck each other up so the universe becomes a singularity again.