Picture tells it all.
Someone at Google is seriously busting their asses to get this good modeling and mapping of cities.
I mean I can see my house modeled in the program, and I can identify it based on the curtains, if I didn't know the physical location of my room.
Then I can fly around and (with a bit of poking in program settings) can enable the buildings in the flight simulator.
Oh yeah, Google Earth has an in-built poor man's flight sim. You can get it started with Ctrl+Alt+A combo. It supports joysticks and I recommend using one, but if you have no stick, you can use the mouse as elevator and aileron. Throttle is page up/page down, and rudder is numpad zero and numpad enter. You can see a representation of all axis positions on the lower left, so it sorta helps if you don't have a stick. F lowers flaps, Shift+F raises flaps. G toggles landing gear.
It's fairly nice though especially on the mountainous areas or (as shown) above modeled cities. However, in their infinite wisdom google apparently thought that the 3D buildings take too much processing power so they disabled them on default; however as you turn the flight simulator on, you can enable them by bringing up the side panel with Ctrl+Alt+B, enable 3D models, then hide the side panel with Ctrl+Alt+B.
Flight model is nothing to be cheered at and there's no real lighting except the pseudo-kind you get from the shadows in the textures, but it's still better looking than Microsoft Flight Simulators even with add-ons - mainly because the frame rates are greater than five with this high scenery density on.
