I don't run any antivirus or firewall software on my Windows 7 PCs (desktop and laptop). I prefer to not slow down my computer, and Chrome has had enough security to notify me in advance on the (very rare) off chance that I stumble across a website that could do any harm.
I've been infected 2-3 times. Every time, it was from downloading software from... less than savory sources of the web, and not running them in a VM first.
