I apologize for the self-promotion here, but my blog recently ran a story that was just a list of links to all the gaming research of the last year and a half basically, with a quick summation of what their conclusions were. You can see that [URL=http://legalarcade.blogspot.com/2008/01/studying-studies-25-things-games-have.html]here[/URL].

I thought it was wonderful all the contradictions that arose once I was finished. Also, great thanks to GamePolitics' archives for letting me quickly find most of those studies.