Yup, what a lot of people wonder about, myself included. I mean society-wise, not Earth-wise. It has to come at some point. Whether the world ends with an explosion of the sun(which I don't think an option; by that time, if we're still around, we'll have had the ability to procreate on other planets), a nuclear war, a disease, or whatever, it's going to happen.
I personally don't think it's likely it will happen in our lifetime... Technology and such hasn't progressed far enough. I feel that once we get to a certain point, that's when it'll all begin to come crashing down. Maybe robots taking over the world or something. Whatever. But think about it: we can only go so far. At some point, we'll have learned "everything". Life is all about learning. Once we "know it all"(obviously, there will still be things like god and the end of space), what's the purpose of life?
If we don't get that far, we're all going to kill each other. Everyone has the ability and capacity to kill, no matter how kind and wouldn't-hurt-a-fly they think they are. If someone is pushed far enough, they will do harm. Period. Whether out of self-protection, beliefs, or just plain anger. And with the current state of the world, I don't think we're going to get far enough to have that too-much-knowledge end above. People are just too angry and short-tempered. I mean, look at the war in Iraq. Pointless, in my opinion. If you ask me, the trade center incident was all planned for America's self-gain. The buildings' insurance was doubled or something shortly before the attack, as if they knew it was coming. The building also collapsed on itself; under the conditions, it should have fallen over. Plus, the building is strongly reinforced, made to take attacks like that. it wouldn't have fallen that easily. The steel would have had to burn for hours to have that effect, but instead, it fell in minutes. Sounds like demolition from the bottom to me. In demolition, the bombs are placed so that the building falls down, not over since it would be a mess. Sounds fishy to me.
Anyway.... I'll let the rest of you get to your ideas.
PUTTING ALL RELIGION ASIDE, I want your opinions on what's going to happen.