I'm astonished you didn't include San Francisco. It's a wonderful city to walk in, with views of the Bay from many vantage points. If the hills are too much of a challenge, what better way to get up or down them than on a cable car? And there's a good bus system if you want to ride and then walk.

... when you start your car and press the gas you do not keep going until you hit a wall. ... Cars could not move without friction between the tires and the street. http://drglickert.com

You missed one of the world's best walking cities: Amsterdam. The very large Centre City--the Canal District--is far more walkable than Hong Kong or New York. There are hardly any cars in that area--mostlyi bicycles--and the cobblestone streets are very narrow with very little parking. You can walk for hours in Amsterdam and you'll see 10 times more bikes than cars.

True yes for Amsterdam.

You hit the nail on the head. That was exactly my thought as I read this article. Amsterdam belongs on this list ahead of most other cities on it.