To me, street photography exemplifies the essence of photography. The instantaneous recording of light through the press of the shutter is paired with brief moments of connection between people, objects, shapes and light. These moments will never happen again. And only through the record of the photograph can we be sure they happened at all.
At it's core, photography is about variations in tone and form. Black and white images capture these forms with exceeding clarity and without distraction.
For some photographs color is an essential part of their composition. Color can sometimes create shifts in tone that otherwise may be lost in a black and white photo. Color is also one of many tools that can provide mood to a photograph.