I never use a virus scanner, most important stuff I do is on a Linux system, which doesn't need any scanner. On my windows system I use mainly alternative/open source software, less vulnerable to exploiters.

Besides, virusses do not exist anymore, at the dawn of computing they were self-reproducing mini programs infecting files or filesystems and thus travelling over floppy's etc. Nowadays it's just crappy software being exploited by simple scripts or maliciously crafted files. Or even complete fake anti-virus packages, built to trick the user, rather than the computer.