If you do install the Media Center pack and you are on a desktop, you might find your computer randomly waking itself from sleep or hibernate at a certain time of the day. If this happens, be sure to modify the mcupdate_scheduled task:
http://support.microsoft.com/kb/979878 (note: for Windows 7, but also applies to Windows 8)
In particular, untick the "Wake the computer to run the task" option under the Conditions tab.
This has been happening to me since installing the MC pack, though the Power-Troubleshooter event wasn't too helpful as it pointed the wake source to "unknown."








