Hi all,
I'm writing you because we are in the final stages of a new version of GeoNetwork opensource version 2.1 (http://geonetwork-opensource.org) to be released early July.
I'm updating a list of links that is included by default in the application and I would like to make sure that page has a concise list of relevant websites that provide access to geospatial data or to important initiatives related initiatives.
I would like to see your contributions reflected, so please provide me with the best link(s) you know 
At OSGEO there's a list with useful links (http://wiki.osgeo.org/index.php/Public_Geospatial_Data_Project) of which I could use some too.
The current list is the following (not claiming to be the best at all and definitely biased towards GeoNetwork catalogs !):
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GeoNetwork opensource related links
http://geonetwork-opensource.org The GeoNetwork opensource Community website contains software, documentation, tutorials, excersises etc..
GeoNetwork opensource Developer website The GeoNetwork opensource Developer website
http://www.osgeo.org The Open Source Geospatial Foundation
GeoNetwork catalogs
FAO Map Catalog GeoNetwork at the Food and Agriculture Organization of the United Nations
DataViz GeoNetwork at the The Vulnerability Analysis and Mapping (VAM) Unit from the World Food Program (WFP)
http://geonetwork.unocha.org/ GeoNetwork at the United Nations Office for the Coordination of Humanitarian Affairs (OCHA)
http://geonetwork.csi.cgiar.org/ GeoNetwork at the Consultative Group for International Agriculture Research (CGIAR)
Spatial Data Infrastructures
http://www.ungiwg.org/ United Nations Geospatial Information Working Group (UNGIWG)
http://www.gsdi.org/ Global Spatial Data Infrastructure (GSDI)
http://www.earthobservations.org/ Group on Earth Observations (GEO)
Standards
http://www.opengeospatial.org/ Open Geospatial Consortium (OGC)
http://www.isotc211.org/ ISO - TC211 Geographic information/Geomatics
http://www.fgdc.gov/ US Federal Geographic Data Committee (FDGC)
Mapping Initiatives
http://www.iscgm.org/">International Steering Committee for Global Mapping
Other related sites
http://earlywarning.usgs.gov/adds/ African Data Dissemination Service
http://www.ngdc.noaa.gov/ NOAA National Geophysical Data Center, NGDC
http://www.nga.mil/ US National Geospatial-intelligence Agency (NGA)
http://www.eoportal.org/ Earth Observation Portal (ESA)
http://www.esri.com/data/ ESRI ArcData Online
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Thanks in advance for contributions. I'll include a maximum of 10 new links to keep the list manageable
Ciao,
Jeroen