MyWOT - The Web Of Trust (WOT) add-on is a safe surfing tool for your browser. Comunity supported browser add-on that will help keep you informed on what web sites are and aren't safe.
Secunia PSI - Free vulnerability scanner for the home user. This software will keep you informed on what software you have installed is outdated and vulnerable to attack. In addition it also provides helpful links to download updates which resolve the vulnverability in the outdated software.
Qualys BrowserCheck - will perform a security analysis of your browser and its plugins to identify any security issues. This free check has a quick scan which does not install anything and a comprehensive scan which requires a plug-in installation. This vulnerability scan is limited to check for browser related vulnerabilities.
Intelligent Software - More freeware, sourceware and other items from an experienced programmer!
The Open Source Advocate - Thoughts and ideas about the open source software movement
Endian Firewall Community - Endian Firewall Community is a "turn-key" linux security distribution that turns every system into a full featured security appliance with Unified Threat Management (UTM) functionality
untangle - The Untangle Lite package offers a collection of free, open-source software applications to run on the Untangle Server. It provides an entry-level multi-functional firewall.
Sysinternals - Great tools I use damn near every day. If you are an IT professional I highly recommended looking into these tools and trying them out.