I've recommended Norton's Anti-Virus ever since Symantec, Norton's parent company, bought into the IBM Anti-Virus technologies in the mid-1990's and took it over in 1998. In 2009, Norton Anti-Virus - which resides under Norton Internet Security and Norton 360 as well - was revamped. It now installs quickly and easily, removes previous versions with virtually no fuss, has a minimal impact on bootup as well as program & definition updates.
For free anti-malware software, AVG Anti-Virus Free 201x gets the nod. Note that if you're a Comcast Hi-Speed Internet (Xfinity) customer, Norton Security Suite (N360) is available for free. Install it from your Comcast connection, though.
Click for Neil J. Rubenking's comparison at PC Magazine:
|The Best Antivirus for 2012|