Well, going by their scores on Acid2, Firefox 3 is aligned with IE8, and there is no alignment between earlier versions of either browser.
But going by their scores on Acid3, Firefox 2 is loosely aligned with IE9, and Firefox 3 might be with whatever version comes after that.
Well, going by their scores on [http://acid2.acidtests.org/#top Acid2], Firefox 3 is aligned with IE8, and there is no alignment between earlier versions of either browser.
But going by their scores on [http://acid3.acidtests.org/ Acid3], Firefox 2 is loosely aligned with IE9, and Firefox 3 might be with whatever version comes after that.