Google maps
Google is making a strong play into the mapping area. First, there was the acquisition of Keyhole, which I must confess, is mind blowingly cool. I have spent a lot of time looking at the cool satellite imagery of the globe. (Not surprisingly, the top of the White House and the Fort Meade area have detail removed.)
And, now Google Maps. It is amazingly fast and the ability to drag the map around is a fantastic usability improvement.