I can not speak for Boston, having never been there, but Philly is a lovely city with a great culture (Yo, Adrienne!) and plenty of fascinating history as well as good nightlife, much more affordable than NYC. (Plus, no tax on clothing in Pennsylvania, so it is a good place to do your low-cost shopping spree!) I used to live in San Francisco and also for a while in LA. SF is a much more compact, wa