GRC: Gibson Research Corporation

Steve Gibson is the owner of GRC.  His two primary points of focus are security research and hard drive recovery/maintenance research.  His hard drive product is called SpinRite and cannot go overappreciated.  It is undeniably the best data recovery app out there so long as the BIOS of your PC can still see the failing drive.

His security research is awesome, thorough and near flawless.  The vast majority of his security research and tools are all available for free.  One of the most important for the average user and for anyone connected to the internet is Shields Up.  This tool is a web based firewall test that checks to see if your PC is visible on the internet in a way that would open it up to attack from certain viruses and from unsavory characters.  I would advise that everyone go here and run a scan if you have never done so.

Steve also does a weekly netcast (podcast) with Leo Laporte called Security now.  It can be very heavy on technical details so for the average person, it could be a bit heavy.  It is, however, always informative.  I listen every week.