I agree with keelbolt. IE is lagging behind way too much.
old skool programmers will find it easier to relate to. IE= Complier, Firefox=interpretor.
IE doesnot know how to start showing HTML until its read the last closing element.
Firefox on the otherhand, intelligently, puts "imaginery" closing tags, to complete the HTML, "as it reads through the page".
You'll notice that in firefix, the stuff starts to happen as the page is loading...even before the </html> tag is read.(use firebug addon to test this on a long html page). Where as in IE, the page will come in a single flash when HTML is complete, which is boring for the user, becuase all this time while the HTML was loading, the user sees a blank page.
On a counter comment, Firefox, does sometimes mess up, if you are usine jquery or other javascript to "manipulate" the html as it loads. On that front, IE performs better and usually does not corrupt display.
Overall I think, the problem is not with your page. Here is an experiment for the staging environment. Get rid of the last three tags on your page
</div></body></html> as well as their corresponding starting elements. Notice the difference in speed in IE ?
Now put them pack because its bad for SEO.
