Best mobile application
I tend to walk alot in town. I'll leave early and walk to meetings, go and grab a sandwich somewhere distant at lunch, skip the metro and trek it instead, etc.
There are gadgets out there like the fitbit that will help you measure your steps and reach your goals but your phone is quite capable of doing the same or damn close.
I don't have targets to reach or calories to lose, but I like keeping track of my rambles. Moves fits the bill perfectly.
It keeps track of your step count/kilometres covered, can do calorie counts if you're into that and traces your movements on a map, including stop locations pulled from foursquare.
It's also great for getting an idea of how long it takes to get to certain places when planning a return trip.