I'm really surprised I haven't seen more buzz about Photosynth from Microsoft Live Labs. Photosynth "takes a large collection of photos of a place or an object, analyzes them for similarities, and then displays the photos in a reconstructed three-dimensional space, showing you how each one relates to the next." This is the most "holy crap, lookit this!" new technology that I've seen in a long, long time.
Go visit the site and give it a try. They have a growing number of photo collections, but I recommend starting with the Piazza San Marco, Venice collection.