I guess a watch might be a step but I was thinking of some future as yet just abstract device.
Lets see what a watch could bring beyond a phone?
I guess touching our skin would allow it to gain some basic information from our bodies.- temperature, ongoing pulse, as well as changes in our body that somehow permeate through to the skin.
A gyro could monitor our activity.
We should also get all the benefits of a fitbit type device.
I'm sure Cortana could do something interesting :
Scenario 1: Pulse high but gyro indicates little movement:, or maybe just pulse erratic - I might want Cortana to text someone close to me?
Scenario 2: (Assuming that the watch measures external air temperature as well as my own): I might want an alert if there was a significant change from my body temperature as compared and correlated to air temperature?
Scenario 3: I didn't go for my daily run the previous day - I might want some encouragement from Cortana (don't forget I am a geek)
I'm sure there are many more ...