Internet Explorer more secure than Firefox?

In the past, I’ve recommended to friends and family that they run Firefox instead of Internet Explorer to gain better security and usability on Windows systems. I’m re-evaluating that stance now that I’ve learned about a new feature of Windows Vista that restricts Internet Explorer and runs it inside of a jail. It’s called [Protected Mode](http://blogs.msdn.com/ie/archive/2006/02/09/528963.aspx), or [Mandatory Integrity Control](http://www.securityfocus.com/infocus/1887/2), and it means that that spyware and adware are less likely to infect a Vista computer.

As far as I know, Firefox doesn’t (yet) run inside the “jail”, so Internet Explorer is probably the more secure choice — yet another reason to admire the technical engineering [effort that went into Windows Vista](http://en.wikipedia.org/wiki/Windows_Vista#New_or_improved_features).

Despite the improved security of IE 7 in Vista, I enjoy the usability of Firefox, including the ability to disable JavaScript from running by default, using the [NoScript extension](https://addons.mozilla.org/en-US/firefox/addon/722) extension. Does anyone know whether there’s a [NoScript extension](https://addons.mozilla.org/en-US/firefox/addon/722) available for Internet Explorer? If not, I’m sticking with Firefox.