Here are a few sources of geospatial data that I have used.
If there are any sources not listed that you would like to share, please share them with me and I will add them to this list. Likewise, please report any broken links below, so I can fix them.
GIS Pilot
http://www.gispilot.com/
Geo Community
GIS Data Depot:
http://data.geocomm.com
GeoCommunicator
Public Lands GIS Data:
http://www.geocommunicator.gov/geocomm/lsis_home/home/index.shtm
Stream Net
Fish Data for the NW:
http://www.streamnet.org/mapping_apps.html
State of Oregon
Geospatial Enterprise Office
Spatial Data Library:
http://www.oregon.gov/DAS/EISPD/GEO/sdlibrary.shtml
Alphabetical List of Data Sources:
http://www.oregon.gov/DAS/EISPD/GEO/alphalist.shtml
Oregon Imagery Explorer
Stream or Download Seamless Rectified Aerial Imagery:
http://imagery.oregonexplorer.info/Plugin.htm
Washington State
Dept. of Ecology GIS Data:
http://www.ecy.wa.gov/services/gis/data/data.htm
Washington State University
GIS Data:
http://www.wsulibs.wsu.edu/gis/data.html