Dolla, there is no one single game that will turn around the PS3.
Why? Case & Point: 360.
The 360 had a huge game in Blue Dragon, combined with another huge game in Lost Planet.
For the PS3, the names are FFXIII and Metal Gear Solid 4. They will invariably, certainly help, but they will not ressurect the PS3 to PS2-type levels.
The key to succuess is lots of decent titles, and not just the few name brand ones. Wii didn't need Mario to move 2, 1m+ games in Japan, neither does Sony. They just need some support.
Next year, I feel the PS3 will be selling around 100% more systems week in and week out. However, this is obviously not as much as it needs.
Also, between the TB Bundle, and Forza 2 shipping to Japan, it's nearly assured that the PS3 will be near 6k by the time TB ships. It'd be fairly easy at that point for the 360 to overwhelm the PS3 and outsell it for 1 week, and even upto 4. Heck, it could constantly outpreform it for awhile even.
What the PS3 needs is what the 360 has had recently in s/w: A absolutely constant slew of decent to good titles, one week after another. The 360 isn't uber-preforming, but it's software is selling well, and the hardware is ty