Kinect for Windows
Microsoft annouced the other day availability of Kinect for Windows SDK. This version can be used to build commercial application, something which wasn't possible with the earlier SDK. Alongside a new hardware device is also available now (priced higher than the earlier one).
While this SDK will work earlier device as well you would not be able to leverage the new near mode support which allows you to detect objects mearly 40 cms from the device unless you use the new device as well. Additionally if you are migrating your earlier code to the new SDK, you may want to use the Microsoft.Kinect.Migration assembly to aid the migration effort.