Here's a bigger list for you, nicely-tabularised. No one size fits all, but I bet they're all nice places to walk around
http://www.carfree.com/carfree_places_old.html
It's a 'what if?' that will have been acknowledged and addressed in any city in the world that has gone car-free. Just needs studying by any new city intending going car-free and the best solution or combination of solutions applied for the circumstances.