Mozilla’s Asa Dotzler: Firefox and more: Building Firefox for Windows 8 Metro
.. we should be able to build a single product, that when installed into the Classic environment via traditional means — a download from http://www.mozilla.org, will be able to become both the default browser in the Classic environment and in the new Metro environment. We’ll, of course, have a Metro-specific front-end that fits in with the new environment, but we will not have to deploy two completely different browsers.
[I]f we do our job, Firefox on Windows 8 Metro should be every bit as capable and integrated with the system as Internet Explorer.
Microsoft had an awful big head start with IE 10 but now that we know what’s possible, we hope to close that gap.
I am seriously rooting for these guys,
Ed Bott (@ wordpress.com) 
Even if their browser isn’t the best, we still need them to push Microsoft to make IE better, same as Google and Chrome. Without them, we will have another IE 6 fiasco all over again!