Here are a few of the science sites that I use. If I get a break over the weekend I'll list some more.
Terraserver - 7.5 minute quads and aerials - similar to Google Earth but with topos
http://terraserver-usa.com/
Defense Science Board - (unclassified) military related science reports
http://www.acq.osd.mil/dsb/reports2000s.htm
Underwater Times - Oceans lakes and rivers science happenings
http://www.underwatertimes.com/
Geological resources and free stuff - including free GIS, works fairly well
http://www.geologicresources.com/free.html
USEPA Clu In - Environmental Technology website
http://www.clu-in.org/
The Daily Galaxy - space science
http://www.dailygalaxy.com/my_weblog/
Aviation Explorer - All things aircraft
http://www.aviationexplorer.com/aviation.html
American Geophysical Union
http://www.aviationexplorer.com/aviation.html
Geology.com - All things geology
http://www.geology.com
Space Daily News - Up to date space business news
http://www.spacedaily.com/