Turning on the System
It's possible to access your Wii U without even turning on the TV. The power button on the GamePad will enable the system, and allows you to access content without touching your TV. The best part - the TV Remote integration will let you then turn on the TV through the Pad itself. Pretty awesome.
But wait, there's more. You can also access the GamePad and turn on your Wii U through the controller's touch screen. Right within the remote interface is a button that says 'Play Wii U' - touch that, and your system turns on. Of course, you can also press the power button on the system itself - kind of how we've been doing it for decades.