There are a number of free and open sources software that one may use to in geospatial analysis or visualization. We recommend the following:
QGIS is available at www.qgis.org
PGAdmin is available at www.pgadmin.org
We use a lot of different open source geospatial software and proprietary geospatial software in the FAST. Geospatial analysis and visualization is about your audienc, the work that you are doing and the resources that are available to you! The software is only a means to an end.