Final Fantasy XIII has sold 5.55 Million Copies

[ShinGundam]

Ok, here we go with PS3 and 360 games on the same list. (Millions of copies)
1)CoD:MW2 - 18.8
2)GTAIV - 14.3
3)CoD4 - 13.5
4)Halo3 - 11
5)CoD:WaW - 10.4
6)Assassin's Creed - 8.6
7)Assassin's Creed2 - 7.5 (interestingly enough PS3 and 360 sales were near identical)
8)Guitar Hero 3 - 6.4
9)Gears of War - 6.1
10)Resident Evil 5 - 6.0 (Sold over half a million more copies on the PS3)
11)FIFA Soccer 10 - 5.8 (good lord who buys 5 million of these every year)
12)Gears of War2 - 5.7
12)FFXIII - 5.5
14)Fallout 2 - 5.2
15)Halo ODST - 5.1
16)Oblivion - 5.1
17)MGS4 - 4.8

Draw your own conclusions.

ٍُSE aimed for 6 million sales of FFXIII and they can pull "International release" adding more content
Cut content from Final Fantasy XIII could create an additional game — Scrawl.