Anyone with a pessimistic view of the world should watch this TED talk by Steven Pinker: it's possibly the best TED talk I've ever watched. It completely demolishes the notion that the world is getting worse with a barrage of statistics that will blow your mind. http://www.ted.com/index.php/talks/steven_pinker_on_the_myth...
Yeah, that talk is excellent. For a double dose of optimism about the human race, follow it up with the Hans Rosling TED talks. First he shows you some visualizations of economic data to convince you that we're not hopelessly fucked, then he swallows a sword. I love that guy.
I've read a lot of Steven Pinker's books, and they were all enjoyable. The ones I've read include:
The Language Instinct
How the Mind Works
The Blank Slate
The Stuff of Thought
