There's alot of things to look at but let's start with previous content this gen from each franchise to see just how much a bundle will influence each console.
First off there has already been a FF product bundled with the PS3 in Japan and that was Advent Children movie on BD along with a demo of FF13. That single handedly spurred the PS3's sales to one of it's best weeks of all time. There hasn't been a bundle with that I know of with any COD game this gen but I'm pretty sure that it wouldn't have lifted the 360's console count too much. Imagine, a MW2 movie, lol no, Final Fantasy can do it because it's just that big.
Second, there hasn't been a main-line FF game this gen so far so it's safe to assume that alot of people are waiting for this game to release to buy a PS3, just look at what the movie/demo did. Do you really think that if IW released a movie/demo and bundled it with the 360 in America that it would bump the 360's sales over 300%? No, yet some people believe that MW2 is so influential, it really isn't, it just knows how to sell well and that's it. But getting back on track here there has been COD 2,3,4 and next up MW2. COD 2 got pretty good reviews and was one of the best launch window 360 titles, the COD fanbase had reason to buy. 3 comes out, meh, then the gem COD:MW comes out and just smashes previous installments so there's major reason to buy then as well.
Now that MW2 is coming out i'm pretty sure that most of the casual/hardcore shooter fans have already bought a 360 for Halo 3/GoW/MW1 so then who would be buying a new 360 for a $100 more? I mean sure the MW2 bundle is gonna sell well but don't forget how many FF bundles are gonna sell in Japan, it could be over 800k. I doubt that MW2 will sell almost a million 360's in America alone while at the price of $400 when catering to a crowd that already has a 360.
I give up, why are we even comparing. DAMN it my fingers hurt!
My vote goes to FF bundle if you haven't already guessed that.