So, you already have an Xbox 360 Slim and you want to upgrade to one of the new Gears of Wars 3 Limited Edition Xbox 360 S consoles with the larger 320GB hard drive. Before today it would have taken a lot of work to transfer all of your data. Now, it will be as simple as using the new 360 S transfer cable that Microsoft has released.
Like the previous Xbox 360 Transfer Cable that allowed the migration of your current hard drive to a new larger hard drive from either original 360 to original 360 or original 360 to new 360 S, the new cable finally makes it possible to transfer from a 360 S hard drive to a larger 360 S hard drive or a new console with a larger hard drive.
The new data transfer cable will be available from Microsoft shortly for purchase in the Microsoft Store. No word yet if the cable is planned for any kind of retail release.