Lived in NYC all my life. This outfit is the absolute fall best:
Varvatos makes the best messenger bags.
Also, layering is great for the city look. Go with white J.Crew undershirts, and a thin cotton or merino crewneck sweater over it, in dark red, burgundy, brown, or even navy. Roll up the sleeves.
And wear either dark tan cords or chinos or blue jeans from Levi's Skinner, or Diesel, Helmut, or Calvin.
Another favorite forgos the layering on top for a slim...