UPDATE Windows Media Center will not be part of Windows 10 and if you upgrade a Windows 7 or 8 machine with Windows Media Center the upgrade process will remove Media Center.
You can read more about Windows 10 Entertainment apps and media servers in my new book.
Official word from Microsoft:
If you have Windows 7 Home Premium, Windows 7 Professional, Windows 7 Ultimate, Windows 8 Pro with Media Centre or Windows 8.1 Pro with Media Centre and you install Windows 10, Windows Media Centre will be removed
You can read about other streaming and media features on our Windows 10 section of TDL
Checkout our alternatives for Windows Media Center in Windows 10
This is the original post but it no longer works:
Windows 10 Technical Preview doesn’t ship with Windows Media Center and we still don’t know if Media Center will ship with the new OS but it is possible to add Windows Media Center to Windows 10. You need to have your Windows 8 Pro with Windows Media Center key that you used for your Windows 8 install and there are a couple of steps needed to get it working.
To get Media Center in Windows 10 go to the search box on the start menu and type Add Features to Windows and then the Add Features to Windows Technical Preview will be show, click on it.
You are then asked for whether you have a product key or if you want to purchase one. You currently can’t purchase one so this is where your Windows 8 Media Center key comes in. Click on I already have a product key and enter your key.
I should say at this point I am not sure of the whether Microsoft want you to use the key to test it so do it at your own risk but my key worked and when you click next it does validate the key. You are then ready to add Media Center. Click Add features to finish it off.
A couple of reboots later and Windows Media Center is up and running.
Hopefully this will work in future builds of the OS and in the final version. So Media Center lives!