A few months back there was an announcement that Nielson was going to start monitoring game play.  Their first report was released and showed some very interesting trends.  To no surprised the most used gaming console is the PS2 which took 42% of total usage in June and 45% in July.  The next best was the original Xbox coming in at 17% in June and 15% in July.  This was a bit of a shock to me because it really shows how many people have not moved on the the 360 yet.  The Xbox 360 was next at 8% in June and 12% in July almost doubling the next console, the Nintendo Game Cube. 

I think this really shows that people have not made the move to the current generation of game consoles.  The PS2 is being kept alive because of their large user base and the easy of porting their games to the Wii. The 360 is the only new console in the top four and is played by more than the PS3(1.5, 1.3) and Wii(4, 3) by significant numbers. 

They also tracked the use of PC games that have been played.  With no surprise World of Warcraft but what was interesting is that Halo is the second most played PC game and Halo 2 is the fourth most played game.  I have not heard how well Halo 2 for Vista has been selling but it does make you wonder if this has helped sell copies of Vista. 

http://www.nielsen.com/media/pr_070726_download.pdf