I've been living and running in Boston for a year now, and I absolutely love it. The Charles River and other bodies of water, plus a relatively high concentration of tree lined paths and trails for an urban area make it a great city to run in. My girlfriend just graduated college, though, and is hot to move to NYC. What's the running scene like there? I figure the cities are rivals in almost every sport, so we might as well debate their running credentials. My vote is for Boston.