The whole of the research on this topic has some very, very serious methodological flaws, which mean there is currently surprisingly little evidence that video games or expert gamers are somehow 'special'. In particular, there are serious concerns regarding [demand characteristics][1]. 

Don't just take my word for it, take a look at the extremely comprehensive and detailed paper on this topic here: http://www.frontiersin.org/Cognition/10.3389/fpsyg.2011.00226/abstract
It's open access, too!

Here's a choice quote:

> One possible factor that could lead to the spurious conclusion of
> gaming benefits on cognition is differential expectations for experts
> and novices. If gamers are recruited to a study because of their
> gaming experience, they might expect to perform well because of their
> expertise, and a belief that you should perform well can influence
> performance on measures as basic as visual acuity (Langer et al.,
> 2010). Imagine that you are recruited to par- ticipate in a study
> because of your gaming expertise, and the study consists of game like
> computer tasks. If you know you have been recruited because you are an
> expert, the demand characteristics of the experimental situation will
> motivate you to try to perform well. In contrast, a non-gamer selected
> without any mention of gaming will not experience such demand
> characteristics, so will be less motivated. Any difference in task
> performance, then, would be analogous to a placebo effect. 
>
> Almost all
> studies comparing expert and novice gamers either neglect to report
> how subjects were recruited or make no effort to hide the nature of
> the study from participants. Many studies recruit experts through
> advertisements explicitly seeking peo- ple with game experience,
> thereby violating a core principle of experimental design and
> introducing the potential for differential demand characteristics
> (Boot et al., 2008;Colzato et al., 2010;Karle et al., 2010). The
> problem is amplified because gamers often are familiar with media and
> blog coverage of the benefits of gaming, so they expect to perform better when they have been > recruited for their gaming expertise.


  [1]: http://en.wikipedia.org/wiki/Demand_characteristics