I think X misunderstood the majority of comments I have seen about the effect a particular game has on sales.
In general no ONE TWO or even THREE games will have a dramatic effect on LIFETME sales. Whenever a huge game is released there is a large chance for a TEMPORARY sales increase lasting upto 3 weeks at the most but usually only 1-2 weeks. Sometimes big games do not cause sales bumps such as Lair or other duds. Games like GTA4 will cause massive sales bumps for the 360 and the PS3. Halo 3 caused a massive jump for the 360 but it didn't last more than a month.
This is not a knock on any system but just stating it for what it is. FF XIII MGS 4 DQ IX and so on will cause noticeable sales bumps but not have an effect on the overall outcome of this gen by themselves.







