Check out this web series: http://www.watchtheguild.com/
It is about people that play the MMORPG called World of Warcraft. Not a show for (your son), but amusing. Could give you insight into possible outcomes of playing these games.
I did watch The Guild. I was amused. And scared. I will definitely enforce my no more than one hour of screen time a day rule in hopes that my kid has a shot at not becoming a complete social misfit. Check it out for yourself and tell me what you think.