Internet security is the combination of Anti-virus, Anti-Spyware, Anti-Spam, Firewall, E-mail Scanner, Identity Protection, Security Toolbar, Anti-rootkit and much more features in any internet security suite.
According to Wikipedia Internet Security is:
Internet security is a branch of computer security specifically related to the Internet. Its objective is to establish rules and measures to use against attacks over the Internet. The Internet represents an insecure channel for exchanging information leading to a high risk of intrusion or fraud, such asphishing. Different methods have been used to protect the transfer of data, including encryption.
So i compiled a list of Top 10 Internet Security suite of 2011:-