ZoneAlarm is an easy-to-use firewall that blocks hackers and other unknown threats.

TrueCrypt is a software system for establishing and maintaining an on-the-fly-encrypted drive. On-the-fly encryption means that data are automatically encrypted or decrypted right before they are loaded or saved, without any user intervention.

Free for personal use, Sygate Personal Firewall provides best of breed security in a user friendly interface, protecting your PC from hackers, trojans and DoS attacks.

New features include full-ICS support, protocol driver level protection, enhanced logging, and more.

Kerio Personal Firewall (KPF) helps users control how their computers exchange data with other computers on the Internet or local network.

PeerGuardian 2 is Phoenix Labs' premier IP blocker for Windows. PeerGuardian 2 integrates support for multiple lists, list editing, automatic updates, and blocking all of IPv4 (TCP, UDP, ICMP, etc), making it the safest and easiest way to protect your privacy on P2P.

Password Safe is an Open Source (free) tool that allows you to have a different password for all the different programs and websites that you deal with, without actually having to remember all those usernames and passwords.

Outpost Firewall gives peace of mind from any threats by cookies, banner ads, e-mail viruses, backdoors, spyware, crackers, adware, and virtually every other Internet danger. Unlike other personal firewalls, Outpost starts protecting against all kinds of internal and external attacks as soon as it's installed. This is the first firewall with an open architecture and support for plug-ins, so its capabilities can easily be extended by thousands of developers worldwide.

Microsoft Baseline Security Analyzer (MBSA) 2.0 is an easy-to-use tool that helps small and medium businesses determine their security state in accordance with Microsoft security recommendations and offers specific remediation guidance. Improve your security management process by using MBSA to detect common security misconfigurations and missing security updates on your computer systems.

KeePass is a free/open-source password manager or safe which helps you to manage your passwords in a secure way.

Comodo claim that their firewall is unique in that it passes all known leak tests to ensure the integrity of data entering and exiting your system.