On a personal note, it is my opinion that video games have not contributed one iota to any of the school violence that has happened recently. I feel it is easier for people to blame things like violent video games rather than the people actually committing the crime. If someone cannot tell fantasy from reality, or right from wrong, then they have far worse problems than playing Doom or Quake could cause. However, I am not saying that all games are appropriate for all ages. That is why they have ratings.
Responsibility starts at home.