Ben Kuchara has a wonderful and balanced article about video game violence in reponse to the recent Connecticut shooting:
Here is a fun thought experiment: if you could do anything, be anyone, or have any power, what would you want to do? Fly? Swim to the bottom of the ocean? Be an officer on a starship and explore space? Make love to a beautiful or handsome man or woman? How far down the list is the fantasy of killing someone? Yet when we open up Steam or walk into a video game store, the killing fantasies are the most popular, and generally the most advertised.