Given that Sony will definitely be pushing the PS3 in the parts of the world that that the PS2 did so well, I wouldn't be surprised to see it eventually reach 18-20M in the rest of the world. I also think there is a definite possibility that it could go on to inch by the Wii.
Having said that, I don't think it was necessary for you to use title bait. "...In the rest of the world" should be in the title.