Hell yeah: Google Earth 4.3 is out, and it looks like it rocks the house.
Progressive-loading 3D buildings are just the beginning; now it has lighting effects (like topography that's affected by sun position, so you can view sunrise shadows and sunset clouds), new navigation widgets for those poor saps without a SpaceNavigator), and—gasp—StreetView integration.
From the look of it, I'll need a new machine sooner rather than later. The best things in life may be free, but they require a faster CPU.
UPDATE: The level of detail and completeness now that they've added so much more 3D building data is mind-blowing:
I love when things just keep getting better and better, ever surpassing the highest hopes I ever had since I was a kid for video games and the Internet all at once...