I'm somewhat of a weather junkie. I love hurricane season, tornado season and rainy season (here on the West Coast.) Google Earth has become a great tool for visualizing the current meteorological data. It's amazing what's available.
For those wanting the latest satellite images of hurricanes and the like, especially during this busy season, look no further than this link. More info about this product can be found here. In my opinion, some of the best images are accessible by, after downloading and running the kml file, selecting "Tropical Atlantic Overlays", "NOAA Imagery", "West Atlantic", "Without lat/lon" and finally the "Rainbow" color scheme.
There are animated satellite overlays as well as computer model tracks and the like.
I also like the Smithsonian's Volcanoes of the World kml. It documents volcanoes including the infamous Toba caldera and Krakatau (aka Krakatoa).