Here are links to software for MS Windows that I find useful. Almost all of it is free.
A nice MP3/Ogg Vorbis player with a rated randomization feature that I like.
A fast image viewer.
A postscript/PDF viewer that will also generate PDF output. Get RedMon and you can print directly to PDF (through ghostview).
A tool for generating graphs (as in mathematical graph theory... not Excel type).
Sun's Java distribution.
An implemenation of LaTeX and supporting tools.
Appears to be a promising add on to LaTeX for generating graphics.
A nice zip/unzip utility. As of version 7.0, this software has become shareware. I would suggest downloading version 6.11 which is still free.
My favorite text editor. It has a bit of a learning curve though. Unix is a Four Letter Word is one place to look for instructions on how to use it.
A powerful Photoshop like image editor.
A simple drawing package for drawing UML diagrams.
I use this for its thesaurus features.
Software that allows you to create and control specialized email address that can be terminated when SPAM is sent to them... nice idea.
A similar service for avoiding SPAM that doesn't require a software download.