We all know if something else doesn't happen first, we'll get some kind of uncontrollably deadly pandemic that'll spread throughout the world and either kill the population or mutate us into something much different than we are now. Sure, there's been some deadly pandemics in the past, but nothing that could change the human race. I just saw "I Am Legend" and it definitely portrayed what would happen if some kind of zombie or vampire pandemic spreads much more realistically than the average horror film, 28 Days Later included. I think as science becomes more and more advanced we'll develop some kind of truly deadly and uncontrollable virus. There's already so many viruses, it's inevitable for one to come that mutates us into something we're not. I'll give it 50-100 years, but a deadly pandemic could happen at anytime, even tomorrow.