CommonSense only goes so far. It wont protect you from seemingly "legit" sites that unknowingly run malicious scripts on your browser, then own your comp. If your going to surf without protection use firefox with the "Noscript" add-on, shit use of the Noscript add-on in general is a good idea. Alot of very talented people on the internets...
*installs Noscript*...forgot last time around.