FFXIII first week sales will outsell Halo 3 first week sales, worldwide.

[sieanr]

Stats87 said:

History shows that the first Final Fantasy game on a new platform sells the most lifetime for that generation. (despite the smaller install base) So I see FFXIII outselling FFXII.

According to this site, first week Japan sales

FF7 - 2.025 Million First Week (Close to 10 Million Lifetime Worldwide)
FF8 - 2.5 Million (Around 8 Million)
FF9 - 2.031 Million (5+ Million)
FFX - 1.9 Million (8+ Million)
FFX-2 - 1.5 Million (5+ Million)
FF12 - 1.82 Million (5+ Million)

FF8 had the biggest debut, but that was arguably the most hyped game ever when it initially came out. Probably because of all the love carried over from FF7.

Personally, my prediction for FFXIII lifetime is 7 - 7.5 Million. Like I mentioned earlier, sales for the PS2(and PSX) have always been ravaged by all the burning of games and piracy. 

Nock out the spinoff (FFX-2) and you see a series that is in a steady decline since FF8. Now, take into account recent changes in the Japanese market, ie big titles selling far below expectations with casual titles dominating the market. Also remember that it is unlikely that the PS3 will be the dominate console in Japan when FF13 launches. With these things in mind its unlikely that FF13 will beat out Halo 3. All systems suffer from piracy, so I dont see the point of bringing it up here. Not to mention that the PS2 suffered from far less piracy than the PS1, especially in the states. Oh, and Kasz216 post above this wins the thread.