At the risk of being hounded from the site, I'd like to recommend this book. It examines the chocolate industry, its emotionally manipulative advertising, the harmful properties of the key ingredients in chocolate, and the use of child slaves and trading practices in the farming of cocoa beans.
At the very least you will look differently at that next piece of chocolate before you put it in your mouth, its mystique and the mythology surrounding it will be taken away...or you might, like me, find that you don't actually find the idea of eating it attractive anymore.
It's a book that is worth a look!