A Flickr account, Firefox, this Greasemonkey script. Hinted at yesterday, in Javascript today! Once it is on the cloud, you can live in the clouds.
Now when browsing images, Flickr adds a visual navigation panel to the right. Finding pictures that are to the North, South, East, West (and intermediates)
My London pictures, being the most accurately geotagged, are now a part of a virtual walk-through.