The latest version of Google Earth is available for download. Read all about the new features on Google Earth Blog, OgleEarth and Lat Long.
Personally, I am stoked about this release for aesthetic reasons (hey, eye candy is important). With the sun and 3D building features, the world looks so much more realistic and beautiful in this version. You may have also noticed that the atmospheric rendering is improved, making views around the world quite lifelike.
Previously an easter egg, the flight simulator now is available by default in the Tools menu. You can fly to some gorgeous views by using the flight simulator and sun feature. Try setting the sun to appear on the horizon, at dawn or sunset, and fly over the Swiss Alps. I should also mention that I've created a new section of the user guide devoted to the flight simulator feature.