Google Earth version 6 brings street views and 3-D trees to the program. Google said:
With Google Earth 6, you can explore the streets in 3D like never before. Fly from outer space down to the streets with the new Street View and easily navigate your way around. Switch to ground-level view to see the same location in 3D.
Now you can see 3D trees in locations all over the world. We have also made it easier for you to know when historical imagery is available in the location you are viewing.
You can download the new Google Earth 6 for Pc, Mac or Linux over here.
Here is a video:
Forum discussion at Google Blogoscoped Forums.