Of all of the great features in Google Earth, the ability to simply zoom in and see increasingly sharp imagery virtually all the way down is certainly the most amazing. With the wide availability of tools like Google Earth, Google Maps, Bing Maps, MapQuest and others we've begun to lose sight of the awesomeness of this simple feature, but it's really quite mind-blowing. Simply by clicking a mouse you have access to terabytes worth of aerial imagery, something inconceivable less than a decade ago.
Google provides a variety of ways to zoom in and out, most of which were detailed in our Navigation post a few months ago.Try using the + and - keys to zoom in and out slowly, or the PAGE UP and PAGE DOWN keys to move more quickly. You can also use the controls in the upper-right corner of the screen, the scroll wheel on your mouse, or (my favorite) a tool like the SpaceNavigator.
Another nice feature to use while moving around is the overview map. You can turn this on and off by selecting it under the main "View" menu.
The entire zooming experience was made much nicer earlier this year when Google released their "Pretty Earth" update. This cleaned up the patchwork appearance that we had all grown accustomed to in Google Earth and helps everything to look much better from any elevation.
What is your favorite way to control Google Earth? Mouse, keyboard or something else?