What do you want from a phone that has an always-on sensors?
I was just thinking of that and it seems there is a lot of things which could be done with the Moto X. Here are some ideas:
Scenario: You forgot your phone near the sink and it just started to catch water
What happens: Humidity sensor kicks in and gives you a warning by playing an alert sound.
Scenario: The phone fell from your hand.
What happens: The accelerometer sensor calculates the correct G-force for such event and shuts off the phone before it hits the ground.
Scenario: You want to take a picture of yourself and everybody around and there's no one to hold the phone at the desired distance.
What happens: Voice command to take a photo should be active by default in the camera app.
Scenario: You held the phone in landscape before you pressed the power button to turn on the screen.
What happens: The lock screen/home screen should start in landscape immediately since the Orientation sensor already knows how your device is being held with the screen turned off.
Scenario: You want to buy a very cheap Moto X dock or wish to make your own.
What happens: It should be cheap and it should be easy to make one. It's just going to have a little magnet and the magnetic sensor can confirm the phone is on the dock. :p
That's all I can think of now. Any ideas? Even if they're a bit wild, roll 'em in.