"In their ideal neighborhood, you could walk to a bookstore and then to an ice cream shop, and your children could walk to school, probably unescorted. (It sounds like so many movie depictions of America in the 1950s.)
They argue that walkability lowers crime - that good people on the streets drive away the bad guys - and that it generally improves life and sharply raises home values. Whether it helps homes retain their value when the market slumps, however, seems a harder question to answer."
This article looks at an August 2009 study by C.E.O.'s for Cities which looks at the relationship between walkability (as measured by the website Walkscore) and housing values.