There's no way to reduce to zero your risk of picking up some piece of malware while browsing. You need layers of security to keep viruses, Trojans, and botnets at bay—the more layers, the safer your browsing. (Of course, the more layers, the slower your browsing, too, so don't get carried away.)
Much emphasis has been placed on the enhanced security features of the latest versions of the popular browsers. Whether one is any safer than another is anybody's guess, but no browser gives you more ways to thwart a Web-based attack than Firefox via its wealth of security add-ons.