EndNote is a program that allows you to organise your references and format them in the reference style of your choice. It includes a Word add-in to so that you can cite while you write.
NVivo is designed to assist in the analysis of qualitative data, enabling researchers to analyse items such as questionnaires, transcripts of interviews and focus groups.
Statistical package for the social sciences which can handle large amounts of data. It offers a wide range of data analysis capabilities and produces results as reports or graphs.
Stata is a sophisticated data analysis, data management and graphing program.