I prefer FireFox as well, but rig IE up with FreeSurfer pop-up blocking and Analog X's Cookie Wall, and it suddenly becomes a formidable contender.

Think about it, if you utilize concepts of least privilege (even without other security mechanisms) it doesn't matter if your applications are secure.
With all due respect, I must say said quote is very naive. You can never afford to be that confident in an application. No matter how awesome your settings are, believe you me there's a user out there who can screw it up so that your security goes down the drain. An application, regardless of its settings, is only as good as the human behind it.