Web browsers, mail clients, and news readers from Mozilla (free)
MS Office-compatible applications from OpenOffice.org (free)
Adam Meade's software for Implicit Association Testing (free)
James Roberts' software for unfolding IRT models (free)
MX Structural Equation Modeling Software (free)
SLEIPNER Cluster Analysis Software (free)
IBM's OS/2 Warp home page (the OS that should have won the OS wars)