Yeah it highly depends on the location you search for. The USA is of course the most tracked and detailed so are important places and buildings.
Satelites, which take these pictures, don't fly everywhere over the world and taking hires pictures like that cost a whole lot of resources and money, thus if they fly over "not important" parts they are mainly used for goverment purposes and not for "leisure" projects like this...
What you can try instead for example are the aereal maps you can find on
http://www12.mappy.com/ (europe) or other street mappers.
eg: For me (Belgium), in Google EarthViewer, the nearest big city isn't even properly visible, let alone my own town, street or house. But when I turn to a local company which takes photo's using planes, you can get something like
this (it's part of my town).
/ 
