To try and combat this problem, Qualys has created a free web browser vulnerability scanner. It works with IE, Firefox and Chrome on Windows and Mac OS. Opera, Safari and Linux are in beta. The scanner checks the browser and plugins to see if they are up to date and will alert you if any vulnerabilities exist. I run this on all of my personal computers and every user PC I come into contact with at work.
https://browsercheck.qualys.com
