It will sell very well.  But 7 million in the first month is a little high probably.  But I will leave you with this.

Halo 3 sold 7.5 million in two years. Why do you think that Reach will sell 7 million in one or two weeks?

No way man o.0

Actually, it sold 7.5 million in 27 weeks.  Week 1 it sold 3.8 million.

http://vgchartz.com/swlaunch.php?reg1=All&game1=Halo+3+-+X360[6964]&reg2=All&game2=&reg3=All&game3=&weeks=100

Except that this is about NPD, and Halo 3 JUST crossed 7.5 million in Americas, thats with Canada and Mexico. It's probably still not at 7 million in America alone and thats after MORE than 2 years.

This is quite literally impossible.

Oh, crap.  That is my mistake.  This prediction is as bonkers as  Gilgamesh's.

stupid logic. Just because it had a high attach rate on a low userbase doesn't mean it will have the same attach rate as the userbase increases. Must own games on consoles with lower userbases usually have high attach rates, it is just how it is. PS1 and PS2 games didn't have high attach rates when the userbase was huge, it's simply too big and diverse.

I thought he was talking about NA only.

He was, it was my mistake.  I apologize.

7 Million NPD,would mean 10 million worldwide o.O lmao