As a cynic, I have a pretty low opinion of the human race as a whole, in it's current state. I try to have faith in the goodness of the individual, though. And I know, no matter how screwed the world does get, it's never going to get bad enough for me to think "what's the point?" The world may be rubbish sometimes, but the hell if I'm going to contribute towards it. I'm going to try and make the world a better place, even if that proves an impossible task.
Besides, it's not as bad as the media like to make out. As has been mentioned, we tend to hear about the horrible things far more regularly than the good, even though the balance isn't that skewed in reality. Accentuate The Negative [http://tvtropes.org/pmwiki/pmwiki.php/Main/AccentuateTheNegative], and all that.