I didn't see any mention of SketchUp in there, so I thought I should throw that one in. It's not so good with terrain, in my experience, but it's terrific for buildings. And it's relatively easy to export the geometry to other programs with better rendering capabilities.

Also, Google maintains a warehouse of free 3d models for SketchUp for use with Google Earth, so if there's a major building you're interested in, chances are good that you can find a reasonably accurate model of its exterior ready-made. I have in the past used a workflow that involved importing a building from the warehouse into SketchUp, then sending it to Blender for clean-up and conversion, and then to Maya (which is definitely not free) for texturing and animation. The texturing and animation could just as well be done in Blender, though.