Google Earth

Well, Google has done it again. Maybe that's why their stock is soaring...
The newest application from Google is called Google Earth. It is the next generation of their prior maps and satellite photos feature.
Though difficult to describe in words, let's just say that this is one of the most fun applets I've used in quite some time. And the best part? It's free! Basically a fully-loaded user-friendly GIS application is now out there for any of us to use. PC World says,

Google Earth is that spellbinding; it ranks among the best free downloads in the history of free downloads.

This piece of software allows you to jump to most addresses in the USA or cities in the world. You can dynamically pan in and out with various layers, in addition to the aerials, turned on. Not only that, but you can tilt and rotate your view dynamically. As well, buildings come in as 3D if you choose (in certain areas). Seriously, although I love maps, and thus may be biased, it's one of the coolest things I've seen online in awhile. It gives one tremendous hope for the potential the future holds for computing.
I would encourage everyone who enjoys technology to download it.