My Updated List:
Anti-Spyware: Spybot - Search and Destroy, SpywareBlaster and Windows Defender (Included in Windows Vista)
Anti-Virus: Avast Home Edition
Browser: Firefox
CD/DVD Burning: AVStoDVD, InfraRecorder and Windows Media Player 11 (Included in Windows)
Disk Management: CCleaner, Defraggler and Recuva
File-Sharing: BitTorrent and Frostwire
Firewall: Comodo Free Firewall
FTP: FileZilla
Graphics: Paint.NET
Instant Messenger: Windows Live Messenger with A-Patch
Media Player/Codecs: Vista Codecs, VLC Media Player and Windows Media Player 11 (Included in Windows),
Office: OpenOffice or Microsoft Office 2007 Enterprise
Technical Tools: Dial-a-fix, HijackThis and Unlocker
Utilities: 7Zip, Dizzy and Foxit Reader
Web Program: Notepad ++
Only Microsoft Office 2007 Enterprise costs money from the list above though you can use the brilliant OpenOffice as an alternative.
Ad-Aware SE Personal, SpywareBlaster, Spybot - Search and Destroy, Avast Home Edition, Comodo Free, CCleaner, Defraggler, Recuva, Windows Live Messenger with A-Patch, Windows Media Player 11, Vista Codecs, Microsoft Office 2007 Enterprise, Dial-a-fix, HijackThis, Unlocker, Dizzy, Foxit Reader, are closed-source / proprietary software / non-free software.
Firefox, AVStoDVD, InfraRecorder, Frostwire, BitTorrent, FileZilla, Paint.NET, VLC Media Player, Media Player Classic, OpenOffice, XPize or Vize, Notepad ++ are open-source / free software.
Any free alternatives to the closed- source / proprietary software / non-free software I would like to try out.
Cheers.