'''OpenGeo Suite Stack'''

OpenGeo Stack is an Open Source GIS stack maintained by [http://www.opengeo.org OpenGeo] and composed of the following elements:

 * GeoServer
 * PostGIS - with Shapefile GUI loader
 * GeoExplorer
 * GeoWebCache

It comes in Community and Enterprise Editions. Enterprise Edition includes technical support and training.
From conferences we've been to, it's gaining in popularity with at least US City, State and Federal Governments.