The best type of antivirus software to protect your PC from malicious attacks is a comprehensive security suite. This will include antivirus, anti-spyware, and firewall protection to cover the major threat categories. Look for a solution that offers a full range of features such as real-time virus scanning, automatic updates, web protection, and automatic removal of malicious files. Many popular security suites also offer additional features such as data encryption, parental controls, and network security.