If you’ve not yet tried Walk Score, it is to me a web site worth having in your favorites list. You enter an address and the site gives you what is termed a walkability score for the address. This score is based on proximity of things like shops, restaurants and such. You get not only the score, but the list of businesses. Site accessibility needs some improvement but you can generally make it work.
Of note is that a couple days ago public transit info has been added to the info about an address. In 40 markets you now get a list of the nearest public transit routes as well as other info that was previously provided.
Walk score can be found at http://www.walkscore.com.
An example address from an apartment I used to live in back when I lived in San Francisco can be found at http://www.walkscore.com/get-score.php?street=75+capra+way%2C+san+francisco%2C+ca&go=Go.
You can read a blog posting talking about the public transit info on Walk Score at http://blog.walkscore.com/?p=344.