Glenn's Free Software Page

Free software for protecting your computer

Includes anti-virus software, firewall software, and anti-spyware software
Free software for protecting your computer
Free Internet utility software

Includes ISP Dialer, Web browser, email, instant messaging (IM), download accelerator, FTP clients, remote control software (useful for helping other people with their computers, or getting help for yours)
Free Internet utility software
Free Utility software

Includes label/envelope printing program, order processing program, file searching program, a compression utility, programming languages, PDF file viewer, Clipboard based Email reformatter.
Free Utility software
Digital Picture Software

Includes scripts for retrieving pictures from many cameras, card readers, and external hard disks. Includes picture viewing, editing, printing, and slide show software. Includes some comments about one way to organize your digital pictures for ready access and simple viewing. Includes comments about digital cameras and scanners as well.
Digital Picture software
Digital Audio Software

Includes playback, CD ripping, audio editing and cleanup, format conversions.
Digital Audio software
Financial Software

Tax software, Loan calculator
Financial software

Best Freeware List is yet another list of useful free software.
Mike Lin has written some useful utilities also.
Optimum X has some nice downloads, and also links to other interesting-looking sources of free software.
Sysinternals has a bunch of Windows internals programs that can be useful, but pretty techie stuff.
Pricelessware is another list of free software, if you are looking for some goodies not listed here. (extinct; last updated in 2009; some stuff on their last list still useful in 2011)