And while biking and walking don't have exactly the same issues they are related. For example using a bicycle for errands is definitely facilitated by having your stops closer to home. That is why I find the Walk Score interesting as a cyclist.
The walk score is calculated based on distances from various amenities like groceries, shopping, restaurants, schools, coffee shops, bars, parks, entertainment, and banking. It will also give a transit score. Here is an example about halfway along my normal commute.
The web site offers ranking of cities but more interesting to me was being able to enter a specific address and see the walking score. It even gives a comparison to the rest of the city.
You can also use a free iPhone app to check the walk score in various places your travels may take you,
Give it a try. If you are really intrigued the site has lots of details on the algorithm and ongoing research.