Our WMS,WCS,and WFS services are powered by a combination of "Mapserver":http://mapserver.org/, "GDAL/OGR":http://www.gdal.org, and "Proj4":http://trac.osgeo.org/proj/ . We do extensive data preparation work using scripts written in Ruby and keep our inventory information in a "PostgreSQL":http://www.postgresql.org/ database with the "PostGIS":http://postgis.refractions.net/ spatial extensions. The vast majority of our data being served is stored as tiled, "deflate compressed":http://en.wikipedia.org/wiki/Deflate, "GeoTiffs":http://en.wikipedia.org/wiki/GeoTIFF.