Doomsday predictions are so cool.
The Mayans supposedly predicted a doomsday event will be occuring on 12/21/2012. Catchy, isn't it. It kind of has a ring to it. While this may be true, a lot of people thought dooms day was going to be 01/01/2000. And then again, a lot of people thought Nostradamus predicted the Chinese would start WWIII in the 1980's.We didn't see much happen, but that doesn't mean something terrible isn't going to happen.
Of course, some natural event is going to wipe out most life forms on this planet. Of course it is. You've seen dinosaur bones in museums and fossils in your own back yard. Even the rocks in your driveway appear to be melted by something. Ever notice that most animals on this planet have the same organs? We're all either survivors, or as I'd like to think of it, children of the last "Doomsday". Like they say, life for billions of years has always found a way. As a whole, it is smarter than we will ever be. I doubt our brains are capable of handling the "truth".
The end-of-the-world as far as you are concerned is much more predictable, and will probably come much sooner. 
Every 80 years or so, all life on our planet is recycled.
If only we could remember where we came from.
All fear of death would go completely away, and the "end-of-the-world" would seem more like a spring shower.
At least, thats the way I like to think of it. I like to think we have and will go on forever,