Some people's predictions can be found here
http://gamrconnect.vgchartz.com/thread.php?id=114292
The lowest prediction is 3 million, and the highest 12.8 millon. The game is currently at 6.12 million, but its sales have dropped considerably recently. However, sales of pretty much everything are down atm, being the quiet season and all.
Lets own up, how confident are we all.
My prediction was put down in a different thread, but I can't find it now. I bet on 9-10 million, which I am feeling pretty confident about still.