Medium-resolution satellite imagery
10 meter:   At 10 meters, it's easy to see roads and water features.
High-resolution satellite imagery
1-2 meter:   At 1-2 meters, you can begin to distinguish the presence of cars and individual houses.
Very high-resolution satellite imagery
.3-.6 meter:   At 30-60 centimeters, you can easily discern key features such as manholes and mailboxes.