P.S. How I draw the line
I don't allow games with realistic violence on real people in real situations. The farthest I bent in this regard was a couple of James Bond games and some game with Ninjas. "Miami Vice" street violence or games where you get points for stealing cars or attacking hookers are right out. Most of my son's games are battles with demons, zombies, and other fantasy figures, and there are more than enough of these to satisfy any kid's "shoot-em-up" urges.