There's an article in the dead tree Wall St. Journal today, page D1, about the effects of video gaming, including World of Warcraft, Call of Duty, etc. The article is fairly positive about the effects, which can apparently include faster decision-making, a better ability to multi-task, and even (in a test of surgeons) better success operating on patients.
One minor downside, the article notes in passing, is that "A meta-analysis by Iowa State University psychologists ... shows violent videogames make people more prone to aggressive thoughts and less likely to care about others."
So, basically, the action/violent games are excellent at building a better, faster, sociopath. Um ... I'm not sure that the article's generally upbeat tone is entirely justified.
I found it interesting, since a similar accusation was leveled at D&D after the "D&D is Satanic" craze began sounding a bit crazy and shrill. The study mentioned in the journal was described as independent from the "companies that sell video and computer games." The way the article downplayed the potentially negative effects of these games made me wonder if the newspaper was quite as independent from those companies as the research was...