Honestly, I doubt we're going to die. We find many ways to kill ourselves off, yet we also find many ways to survive, and even if nuclear war were to happen, there's tons of safe places for small pockets to survive and thrive. As for the other theories, those won't happen for thousands of years, and seeing as how within 60 years we went from learning how to fly to landing on the Moon, I'm sure we'll have colonized other planets or even other galaxies.
For those who say "Alien Invasion." I honestly always wonder, as we constantly think the Aliens came before us and are technologically advanced beyond ability, but what if WE'RE the older race and more technologically advanced? It's possible we might find another civilization that's rather new, and then we're the invaders. Lastly, each planet is different, so being born on Earth makes us use to it, and the invaders would either have to have extremely special tech to compensate, or born on a similar planet (mass similar for gravity, same elements, oxygen and nitrogen count, whatnot) that it's almost a moot point trying to compensate.
(I believe I over thought that, but I'm learning a great deal of space for my military studies, and we know simple things that would make stuff like this extremely difficult. Not impossible, but implausible.)