How is this one for a unique mapping site?  A9.com offers maps of major U.S. cities that allow you to view the map location at the street level on both sides.  You can search for a specific address or just travel the street by moving the magnifying  glass along the map layout.  You can also "walk" the street virtually by moving the arrows on the picture frames.  Try the A9 map search out for yourself at maps.a9.com .