Washington Post columnist Sebastian Mallaby writes a sensible op/ed about how video games can be and are often educational. He also puts the kibosh on the notion that video games lead to violence, to wit:
The new wisdom begins by questioning the idea that computer games cause violence. Lab tests have found that people do become aggressive right after a bout of zapping virtual enemies, but tests conducted outside labs have found no such result. For example, Dmitri Williams of the University of Illinois has tracked the behavior of a group that played a gory monster-slaying fantasy game regularly for one month and compared it with a game-free control group. The fantasy killers were no more likely to lose their tempers in real life.
Of course, this is a point that we at Reason have been making since, oh, the last century.
In addition, video games are part of the modern world of television, movies, pulp fiction, computers, the internet, advertising, and better nutrition that combined have been actually increasing average IQs for a couple of generations. This rise in average IQ is called the Flynn Effect, after New Zealand sociologist James Flynn who first reported it.