For all users, from individuals to small offices to big business to government, we most strongly recommend use of the Zone Alarm family of products. Zone Alarm itself is a fabulous firewall. PC's should also be protected by Zone Alarm's anti- spyware and anti- adware products.
We have boiled down our most actionable information into our hard-copy book available at Lulu.com at: http://www.lulu.com/security