I don't know what to believe but I can tell you what I'd like there to be.
I would like to think I am a spirit with a body and will pass on to some kind of astral, spiritual plain. I do not want to reincarnate and return to a world I mostly hate and as somebody I wouldn't want to be, but I sure don't like the idea of there being absolutely nothing. As I exist, I can't imagine the idea of not existing (not that I can't imagine the possibility, but that I can't imagine what it would be like because it would be nothing), which is obviously something no human can exactly imagine as it contradicts existing. Of course, if that is the case, I won't have to worry so much as I won't know, see, hear or feel a thing, whatever that's like...
I usually just picture black, but there wouldn't even be that. *shivers*