For those of you who have tried Microsoft Windows Vista Beta 2 with their Xbox 360's through the Media Center and its Extender functionality, here are two known issues that you may or may not have run into.
The first issue is that you may have noticed that the transitions and animation are not available through the Xbox 360 Extender. This is intended as noted below here.
Transitions and animation not available on the Extender
Description: The smooth transitions and animation available on the Media Center PC are not currently available on the Extender. You will notice the differences between the PC and Extender experience as you navigate through start menus and change from one feature area to another. UI transitions and animations on the Xbox 360 will be enabled in a future update.
As for another known issue, for those of you who have had the "Wrong Region, This disc's region code is incorrect for this console" error, the Xbox 360 Extender bits in Vista Beta 2 are for Region 1 only. Microsoft plans to open up the Extender functionality to other regions later on in the beta.
Hope this clears up two things that have been commonly asked about Microsoft Windows Vista Beta 2, Media Center and the Xbox 360 Media Center Extender functionality that is found in the current release.