I think Halo 3 is too low. I mean Halo 2 is still selling quite well in 2007

In fact I think underpredicted fable 2, Mass Effect, and Halo 3. Those are HUGE games and even COD 2 did 2 million easily

I still think Halo 3 will at least beat Halo 2, and Fable 2 and Mass Effect will along side Gears of War type sales at 4-5 million

Halo 3 isn't Halo 2. And most of the time it's hard to sell more units than a previous installment into a series UNLESS, it has some dominating cool new feature that allows it to appeal to more buyers. Such as online in Halo 2 over Halo 1's case.

I was pretty shocked at Brawl too but I hope it happens....

It does have a dominating feature. The 360 is more popular than the original Xbox and is currently outpacing Halo 2. Its already at 6 million in only 2 months!

 We mean a real dominating feature.  The main issue that's stopping it is unlike with the Xbox, Halo 3 has competition on the 360.  Halo 2 had no competition software wise from another brand on the Xbox.  This will slow down sales dramatically.  Now how much H3 can sell I don't know.  It may pass up Halo 2 simply becuase 360 will sell more than Xbox.  

Halo is established now as the "mario" of xbox. That alone will sell it very well for a long time. Its a "must have" for all xbox 360 owners. Halo 2 is only marked down to this day at $30 and is still selling quite well

I think it is possible for Nintendo to sell 1 mil this month in the USA. If Ninty can put that many in the stores, they will sell.

It's more than possible. Wired Blog did an analysis of past NPD data and determined the average increase from Oct to Nov was about 250%. One million would actually be below that average.