Here are some of my favourite free applications for Microsoft Windows. I have not sorted them into categories, it's just a random list.
Firefox - web browser download
The best web browser you can get. Version 2 was good but 3 is a great deal better, using less ram and system resources to perform. Fast, safe and has lots of great features. Also available as a portable application that you can run from a flash drive. Hundreds of add-ons available to extend functionality.
Opera - web browser download
My second favourite web browser. Very fast and some great features and of course fully standards compliant.
AVG Free Edition - antivirus download
A very good free antivirus. Even has a built in Firefox add-on that checks links for malicious content before your browser goes there. Regular updates and doesn't consume system resource like some other antivirus programs.
ZoneAlarm - firewall download
An outstanding free firewall. Blocks hackers, detects and prevents unwanted intrusions. Gives you full control over which of your applications can access the internet. Don't rely on the built in windows firewall as it only monitors inbound traffic.
Spybot Search and Destroy - antispyware download
An adware and spyware detection and removal tool. The best free one available. It's not perfect(no antispyware tool is!) but it provides the best protection you can get for free. Weekly updates.
SpywareBlaster - antispyware download
A good program to install to support Spybot S&D with no conflicts. Prevents the installation of adware, spyware, browser hijackers etc. You have to pay for autoupdates but manual updating is free and simple, just remember to do it!
CCleaner - system optimization download
A great tool for removing the junk files that windows generates, tidying up your registry and freeing space on your hard drive.
RegSeeker - registry cleaner download
A great tool for managing several popular registry items and searching the registry by keyword. It offers quick access to Startup Entries, Uninstall Information, Colour Schemes, History items (URLs, Recent Documents etc) and IE Favorites. The program also includes a registry cleaning feature that finds invalid and unused registry entries, allowing you to delete them. RegSeeker can automatically create a backup before deleting any registry entries. No installation required just extract the zip file to your hard drive or a flash drive. This utility is not intended for complete beginners and you should feel comfortable working with the Windows registry before using it.
HoverSnap - screen capture download
A brilliant lightweight screen capture program. Can save as jpg, png, bmp or gif files. No installation required just extract the zip file to your hard drive or a flash drive.
7-Zip - file archiver download
The best file compression utility for windows, and it's free!
FileZilla - ftp client download
A fast and powerful FTP/SFTP client with many features. It includes a site manager to store all your connection details and logins as well as an Explorer style interface that shows the local and remote folders and can be customized independently. The program offers support for firewalls and proxy connections as well as SSL security. Additional features include keep alive, auto ascii/binary transfer, download queue, manual transfers, raw FTP commands and more. A nice program for beginners and advanced user alike.
MP3Gain - volume normaliser download
Analyses and adjusts mp3 files so that they have the same volume. Essential and easy to use tool for music lovers.
The Godfather - audio file manager download
A great audio fie tagger and manager with many features. Not the easiest to use but once you learn how you'll be glad you did.
Super - media file converter download
Converts(encodes) almost any type of type of audio or video file. Very easy to use.
Audacity - audio editor and recorder download
Does everything you need to record and edit audio. You will need the LAME Mp3 encoder if you want to export your audio files as mp3 instead of wav. Easy editing and content filtering, including noise removal.
Gimp - graphics editor download
There are better editors that have more features and are easier to use but they cost a lot of money and the gimp is getting better with each release. So if you don't want to pay hundreds for the commercial products the gimp will meet nearly all your needs - it works for me!
Open Office - office suite download
A free office suite of tools to install on your desktop to create documents, spreadsheets and presentations. It is compatible with MS Office, so you can read and edit existing word, excel and powerpoint documents. You can also convert your materials into PDF files for free.
Notepad++ - editor download
Very powerful and versatile source code editor. Supports a huge range of languages - ideal for hand coding.
UTorrent - bit torrent client download
A really good p2p client. Light on resources, easy to configure and powerful.
VLC Media Player - media player download
A Free and Open Source cross-platform media player that supports a large number of multimedia formats, without the need for additional codecs.