I say after two weeks.

As it stands now, GoW WW is roughly 4.56m, will be around 4.6m by next week.

I think that after two weeks, Halo 3 will be past that, and be around 5.5m.

What say you?

EDIT
------------------------------------------------------------------------------
Week 1 Halo3 = 3.83m             Gears of War = 4.69m
Week 2 Halo3 = 4.64m             Gears of War = 4.72m
Week 3 Halo3 = 5.05m             Gears of War = 4.76m ******* Winners!!!!*****

Well I lost. But, it was damn close. Only about 80,000 units off. Granted, that is within the margin of error, so theoretically I could be right.

Winners that picked 3 weeks:
SP3NCY1325
Stevetrop

Everyone else are losers. Especially those who didn't play.  

Two weeks might be pushing it, even for Halo. I would say it will probably be at around 3.5 million after 2 weeks, but maybe I'm underestimating the uber ad campaign.

4.6 Million Hmmm.....well I assume Halo 3 will sell perhaps 3 Million Week1, but then sales will slow drastically, I say 4.8 Million in a Month.

Although Gears of War could very easily see a sales boost too from all the new Xbox Owners.

3 weeks

I will say 5 weeks.

Ummmmmm ...

November.

1.7m first week. 2.8m in a months time. 5-6m by years end.

First day.

2 1/2 months.

You'll be in for a surprise.