Street level pictures on A9 [www.amazon.com]
I'm a little chagrined (or vindicated) to see this, because it's an idea I came up with about a year ago. Nice to see it implemented without having to do the work myself!
My idea was a little more collaborative -- the ability for any user to upload GPS encoded photos. You then could look at an overview map which would show how densely people have uploaded pictures in particular areas, and you could take virtual tours of those places.
You then would need a way of determining which pictures were the best in a densely photographed area. Probably some sort of rating scheme.