The gap is 3.26M.
Now, I expect the Wii to sell around 9M more by the end of the year (10M is max). So do you expect Ps3 + X360 to sell less than 6-7M combined? No way. I expect them to sell 8M at least.
http://www.vgchartz.com/games/userreviewdisp.php?id=261
That is VGChartz LONGEST review. And it's NOT Cute Kitten DS