GeoDa is a powerful Open Source GIS, designed specifically for analysis using spatial statistics. GeoDa enables users to create thematic maps, and a series of charts that are interlinked. The example below explores unemployment rates from 1960-1990 using GeoDa.
Another useful Open Source GIS is GeoViz. GeoViz allows users to create bivariate maps and engaging scatterplots. The example below explores unemployment and family poverty from 1960-1990 using GeoViz.