The Project for Public Spaces has an interesting list of Great Public Places, incuding buildings and streets as well as parks and markets. There's also a Hall of Shame for places that are empty, uninviting, disorienting and inaccessible.
Area sites in the thumbs-up list include Post Office Square (Boston), Boston Common & Public Garden and the Minuteman Bikeway. Widely-detested Boston City Hall Plaza makes the Hall of Shame.
They've also posted guidelines for What Makes a Successful Place (hint: accessibility, comfort, sociability and activities taking place), as well as Why Spaces Fail. These are important issues as Framingham begins revitalizing downtown and Natick oversees a major mall expansion, because even smart people can get it wrong. And once you've got a bad development, it can take decades to get rid of.
Why did Boston's Lafayette Place fail so miserably, while Copley Place not only succeeded but added vitality to neighboring Newbury and Boylston streets? Why is Quincy Market such an appealing public area and Boston City Hall so ghastly? Integration with the neighborhood, creating an appealing streetscape that people want to linger in ... these are key for nurturing a successful commercial center.