This  map of the New York City Subway System, as developed by the Metropolitan Transportation Authority, shows the depth and reach that the MTA provides in NYC for commuters and tourists alike. Being familiar with New York myself, having the subway at your disposal is great. What is even greater is a detailed and system-wide map of all the routes and the boroughs they provide service too. Having a colored map in rich detail that somewhat simplifies the navigation of NYC by train is a wonderful tool to have. Although this map is large scale and only encompasses a single metropolitan area, the detail and reach of the MTA Subway  is immense and shows an interesting transportation link in comparison to the road network  of New York City. The map is able to cleanly represent the range of lines by color, number, and letter without cluttering the image and the legend clearly defines what each symbol means. Although daunting at first, this subway map is able to provide the average user with a quick and easy tool to navigate through the Big Apple with ease.
http://www.nycsubway.org/wiki/New_York_City_Subway_Route_Map_by_Michael_Calcagno