This free service offers detailed street and terrain maps, robust locator tools to find addresses/businesses/places, and a route planner for traveling by car, public transport, or walking.
Live traffic conditions for several cities are available as well. For those who need visual cues, Google Maps provides that too. Its fascinating "Street View" shows 360° panoramic street-level views, inviting users to virtually walk and explore the area. This is available in many U.S. cities and in several countries abroad. There is also a feature for those wanting to create their own maps. No more fumbling with folding paper maps, just click on this great site.