The following are software I personally endorse. Criteria: used almost daily by myself, and few/no substitutes accepted. This is quality software, and I want to support the developers by sharing my enthusiasm for their work. - Jem Berkes, PC-Tools.Net
Recommended by PC-Tools.Net
OpenOffice.Org office suite - An entire office suite, free. Runs on many platforms, is very stable, and seems to work just about perfectly.
Slackware Linux - This Linux distribution is lean, easy to install, and expertly put together. Slackware is nice to tweak and configure because it has a straightforward structure, and things aren't hidden behind layers or interfaces. Pat Volkerding has created one sleek Linux distro. I have purchased Slackware CDs, but you can also download it free.
Mozilla Firefox web browser - Previously, one of those "best kept secrets" but rapidly gaining popularity these days. Firefox is now breaking through, and my own web site stats support this. Firefox runs on many platforms, is fast, glitch-free and likely more secure than Internet Explorer. Very stable in all my testing, and has lots of nice features.
SpamProbe spam filter - A very fast, Bayesian spam filter for UNIX created by Brian Burton which classifies spam so accurately that I no longer care how much spam I receive; I never see any of it. "Best kept secret" of the anti-spam world.
PuTTY telnet/SSH client - Stable, light, powerful, and extremely functional. If I'm running Windows this is the SSH client I reach for immediately. Simon Tatham has done a very nice job with PuTTY, which is tool #1 for remote access.
IrfanView image viewer/editor - Fantastic image viewer which, over the years, also became somewhat of an image editor and retoucher. An invaluable tool on Windows. My preferred way to scan images (supports TWAIN). Irfan Skiljan has put a lot of work into IrfanView, and it shows.
Nullsoft Winamp media player - Over a large span of years, has remained sleek, functional, and free of irritations. Winamp has a pleasant interface, supports a huge number of media formats, and is stable.
Xnews news reader - Luu Tran's USENET client for Windows. Has all the features you need in a USENET client even for advanced use (kill files, scoring, etc.) Has a nimble interface, and works flawlessly.