What if there's no light at the end of the tunnel?

Yeah.
So I've been cooking up a plot for a short story I wanted to write recently. It has something to do with life and death (cliche?) so it had me thinking about the afterlife. There are so many versions of the afterlife that I'm not sure which version is true anymore (which version is true to me anyway). Death is inevitable to all mortals, and sometimes I think that all these 'versions' of the afterlife cropped up from people's fear of disappearing completely forever. Some say there's a really peaceful, bright, happy place where all suffering is void awaiting us when we die. Some pessimists may use "see you in hell" as their last words. Then there's the popular reincarnation theory that inspired so many stories, shows, manga and whatever I read or watched before. Back in Form 2, a friend of mine told me she believed we'd simply meet our utter end when we die (no afterlife). These are some of the traditional and popular versions of the afterlife I've heard. Who knows how many more are out there...Which do you think is true?
For me, I dunno. I'll know on the day my body completely fails me (and I'll meet a shinigami and be taken to the Soul Society lol). Occasionally, I see this quote posted on my friends' blogs, Facebook, twitter or wherever they can post:

"You only live once, so make the best out of your life"

Or something like that. I've started wondering what's their reason supporting this quote. There should be a few different ones for different people. I should ask them that one day. Usually, I would disregard its existence, at most it would irritate me just a bit. Now it piques my curiosity (I'll be more careful than the cat, don't worry). If they believe there's a happy afterlife, then I guess it's more like a retirement from life on Earth and migrating to that paradise so high up that even with the most powerful telescope in the world you won't be able to see it. I can understand 'live' only once if they meant going to hell (they'd be tortured all the time, so it's not considered living a life isit?) What about achieving nirvana? Uh...for some reason I don't think it really applies here. Or do they mean that our end's like the end of a book? My scope is really narrow in this post, I don't want to make it too long anyway. It's just a small piece of my opinion.
I tend to use the reincarnation theory a lot when I'm talking about the afterlife with my friends or as inspiration. Life's almost like a game to me, and it kinda sucks if you can't create a new character when you're done with an old one.