Google Earth

Google Earth is one of the most jaw-dropping pieces of software I have ever seen. Google says you can use it for planning trips or to find businesses, which you can. The wonder of it, though, is the ability to explore the world in 3D, the whole, amazing world. Unlike traditional mapping services, Google Earth shows you satellite imagery on top of which you can overlay road maps or political boundaries. You can see businesses and buildings. Mountains and molehills (maybe not molehills). The data is updated via the internet, so you always have the most up-to-date info available.

Not only can you view everything, you can actually tilt the map to see topologically correct terrain. You can see how tall Everest really is. You can see Niagara Falls. Major cities even have their buildings represented in 3D. Visit the Las Vegas Strip. Gaze at Manhattan's skyline.

Another fancy feature is the ability to download extra information from 3rd party groups like, say, WiFi hotspots, or crop circle information.

All expected mapping functions are there as well, of course. Adding locations, route planning, etc. It's all there. I bet, though, that you spend a lot more time sightseeing than planning trips.

http://earth.google.com/