Google Earth is REALLY Cool!
Even the free images are pretty good and you can do some cool effects as well. Here is a satellite shot of my new apartment (actually the whole complex) in Lincoln...
That smudged grey line is where Google Earth stamps the address. I have not learned how to change address stamps or create icons to replace them yet. I should pick it up soon as the learning curve for KML, like HTML is not that sharp.
My major beef with Google Earth is that it is not available for the entire globe like Keyhole's subscription service is. For most, this is no big deal because much of North American is covered in great detail. But if you are looking to expand a project to other continents you will have to subscribe to the Keyhole subscription service (a bit pricey). Google Earth Pro is available at a commercial premium but if you are willing to fork that over you might as well aubscribe to the Keyhole servers. I hope Google Earth is expanded soon to include all of the data Keyhole has available on a global scale. (I'm sure this is in the works already!)