New York City!
The Big Apple, one of the biggest cities in the world has plenty to do for the walker in you. With day trips to the local islands to take in the history of the city or just walking all over the place to see all the famous sights, this really is a great place to walk.
Avoiding the subway is the best way to see the city and Manhattan Island has so much to see, from Central Park in the north, to the world trade center site in south, Broadway, Times Square, Chinatown, and the fashionista districts in between. There is an endless list of places to discover and explore.