Here’s the free (it doesn’t cost money) Windows software I use.
Camstudio – Record screen video. Free alternative to TechSmith’s Camtasia.
Screenshot Captor – Capture, edit, and publish screenshots. Free alternative to TechSmith’s SnagIt. Very nice output.
AVG Anti-Virus – Antivirus. Effective.
CloneSpy – Duplicate file finder and remover. Saved me a bunch of time sorting through gigs of data I’ve accumulated over the last decade or so.
Inkscape – Vector-based drawing program.
Paint.Net – Image effects and simple editing. The “glow” effect is the best.
Notepad++ – Easy text editor with programming language syntax highlighting.
PuTTY - SSH client.
WinSCP – SFTP and FTP client.
7-zip – Archive extractor. WinZip-like.
FreeMind – I’m not completely sold on this one, because mind mapping works much better (for me at least) with old fasioned pen and paper.
VMware Server – Host virtual machines. Much better than dual-booting.
For writing documents, I use TeXLive under OpenBSD (under VMware), particularly XeTeX. It’s a shame that word processing is still so difficult. It would be nice to have the ease-of-use of blogging software, or some wiki stuff, and then render it with XeTeX.
Scribus works well for deskop publishing, if you’re a WYSIWYG sort.