Remote sensing and satellites
The Gateway to Astronaut Photography
The Gateway to Astronaut Photography of Earth hosts the best and most complete online collection of astronaut photographs of the Earth from 1961 through the present.
NASA Earth Observatory
Current satellite images with Earth Science description
Earth Lights at Night
This composite image shows points of light on the Earth at night, illustrating areas of industrial activity.
This magnificent, constantly updated site actually has much more than space weather, though it has that in detail.