Google Maps has added two useful features: subway stations and building outlines. The subways are indicated with an M on the map (Metro? MTA?), and the building outlines can be seen, faintly, in magnifications at the top two zoom levels. For instance, you can see them here, around Broadway and Lafayette.

You can get similar info at OnNYTurf and PropertyShark, but for those of you who already use Google Maps, this is definitely a handy little addition.