I love huge photos. I love to be able to zoom in several times and have it be just as clear as the original picture. Wikipedia has a list of the largest photos in the world and GigaPxl is always a fun way to see some great large photos and zoom in.
The current largest photo in the world is of Delft, Netherlands. Using a flash-based tool you can pick an area in the picture and zoom in on it. I chose the road on the right and read the license plates and street signs as clear as day. I also read the clock on the tower way off in the distance. (It was 3:05).
I feel like James Bond.