Funny story...
My new MacBook froze on the train in to New York the other day. Arriving in Grand Central and in not much of a rush I decided to visit the Apple store and ask for a bit of help. I waited for a 'genius' and he asked if I'd try to restart it. At that moment I realized that I actually didn't know how to restart it. The power button, familiar on my previous generation's machine is absent with the new one. With the ribbon bar it appears to not have a power button.
I mentioned this and he says something to the effect that the button still exists but doubles as the finger print reader. He pushed that and the machine restarted.
I then said. "Oh, I didn't know you could restart it there because once I heard it was for the finger print reader I vowed to not touch it".
He laughed.