JDMP

If you are interested in data analysis or machine learning, the following list might be helpful for you.

Commercial Software for Data Analysis

Matlab
Powerful programming environment for data analysis

Free Software for Data Analysis

Octave
A free replacement Matlab

R
Free software environment for statistical computing and graphics

PSPP
A free replacement for SPSS

Gretl
Cross-platform software package for econometric analysis

Weka
Collection of machine learning algorithms for data mining tasks

RapidMiner
RapidMiner (formerly YALE) is an open-source system for knowledge discovery and data mining.

MALLET
MALLET is collection of Java code for machine learning applications to text

KNIME
KNIME is a modular data exploration platform developed at the University of Konstanz