All good, all free. Everyone running Windows should try out this software. Period.

Keep Secure:

• Panda Cloud Antivirus – Lightweight and effective.
• Malwarebytes’ Anti-Malware (free version) – For manual malware removal redundance.
• Sunbelt Personal Firewall (free version) – The best combination of a lightweight & effective firewall I have found.
• KeePass – Store all your passwords securely, because you HAVE TO use different and more complicated passwords than can be remembered.

Stay Tuned up:

• Advanced SystemCare Free – Best allround tune up (be sure to un-check “start with windows” in the options after you install it).
• Revo Uninstaller – For completely removing software you don’t want.
• Defraggler – Defragment your hard drive every month, and use this.

Now get stuff done:

• Firefox – Faster and more secure web browser than Internet Explorer
• Thunderbird – Faster and more secure email client than Outlook/Outlook Express
• OpenOffice.org – A full office suite for starving students and frugal businesses alike
• Paint.NET – Great image editor, for all your picture-cropping-and-red-eye-removing needs.
• Google Earth – See Earth from above (not to mention the Moon and Mars)!
• VLC media player – Not flashy, but it can play almost anything… even corrupted or incomplete media files.
• Sumatra PDF or Foxit Reader – Both are way faster and, again, more secure than the standard Adobe Reader.
• CDBurnerXP – Great free CD and DVD burner.
• 7-Zip – Open pretty much any compressed file you come across online.

There is, of course, lot more great free software out there, but I would call this a good baseline selection.

What must-have free software do you use?