Going the Distance - The Wall Street Journal
The Wall Street Journal's Going the Distance Marathon comparison tool has the route of this Sunday's Chicago Marathon. The map includes the Chicago Marathon route, an elevations chart and Street Views of the route.
The Wall Street Journal Going the Distance application also has Google Maps of the Boston Marathon route, the New York Marathon and the San Francisco Marathon. Each route is accompanied by an elevation chart and Street View.
My favourite feature of the Wall Street Journals maps is the superb integration between the elevation chart and Street View. If you hover your mouse along the elevation chart the Street View will update to show the respective view. Very cool.