According to the Microsoft press release below, Gears 2 pre-sale orders are already more than Gears 1 pre-sale orders with 24 days still to go till launch. This bodes very well for a huge first day/first week for Gears 2.
Putting some VGChartz numbers in, Gears 1 sold ~880k in NA/EU regions on the first week and Gears 2 will be be a simultaneous release on Nov 7 for NA/EU. I wouldnt be surprised if this number is doubled to ~1.5m to ~2m first week debut for Gears 2.
As a comparison to the most recent HD blockbuster, MGS4 did ~1.7m on its first week for all regions NA/EU/JP simulataneous release. I am quite sure Gears 2 can match or even exceed this first week level in NA/EU regions alone.
Source: http://gamerscoreblog.com/press/archive/2008/10/14/561859.aspx
Gears of War 2 Fans Worldwide Preparing for the Countdown to Launch
“Gears of War 2,” the blockbuster sequel to the fastest-selling game of 2006, recently surpassed the total pre-sale orders of the original “Gears of War” and is poised to become the must-have video game this holiday season. With “Gears of War 2” now just 24 days away, there is plenty to look forward to when the game launches on November 7th.
