I voted for NUKELEAR WORZ!, just cuz it made me laugh. On a serious note, I think there are really only two major possibilities for our species.
1. We go the way of the dinosaur, it doesn't really matter how we go, the end result is the same.
2. If we somehow manage to not kill ourselves, eventually we won't really be us anymore. Natural selection will have taken its course and we evolve into something more advanced, like comparing ourselves to chimpanzees, we will no longer be the dominant species of the planet.
Either way, I think eventually humanity's time will end, it's the nature of things.