Try a Point and Shoot 35mm
I am a fan of medium format (Rolleicord) for slow action, but for fast action or night street photography I have found that my Rollei Prego point and shoot 35mm allows for very quick shooting with accurate auto focusing. It is especially useful at night where the auto flash in effortless. Also, the lens is surprisingly sharp and variable. I feel it rivals my old Nikon SLR's in sharpness in 8 x 10's.
Here is an example of some recent work put in a book. Many of the photos were taken with the Rollei Prego: http://www.blurb.com/books/2781221