A company named Mobile Gmaps has published a set of downloadable Google Earth files that pull in street maps, topo maps and aerial/satellite photos from Google, Yahoo, Microsoft and more. The Google 'terrain' maps feature high resolution topo maps with stream names, shaded relief, labeled contour lines and natural features. If you want to determine which drainage got the most rain from a recent storm, you can overlay live storm total precipitation maps from the National Weather Service on the Google terrain maps. Combine these two map layers with put-in locations from AW's web server and stream and precipitation gauges and you've got a valuable arsenal to prevent getting skunked the next time you chase the rain. You've also got a good toolkit to do recon for your next wilderness paddling adventure.
The aerial and satellite photography from these map providers is often higher resolution than the default imagery provided by Google Earth. These other imagery sources may also provide a glimpse of the landscape in different seasons.