PC Magazine has come up with a list of the Best Free Software (2/8/08). 157 software tools; no fees; no expiration dates; and sometimes no downloads. The article divides the list into categories such as Hall of Fame, Antivirus, Firewall, Security, Finance, Office, Utilities and others.
Check out their list at http://www.pcmag.com/article2/0,2817,2260070,00.asp
As with all free software, make sure you read User reviews and Ratings and have a recent backup of your system before you install any software.