I dont buy it. Some features just aren't reasonable to do without js and the number of people without js is tending towards vanishingly small, and you can have a nondegraded experience for a very significant percentage of traffic by not just dismissing all versions of IE. Not that you should support all versions, but if you are sending a separate no-js version to IE10 then you are doing it wrong.

In my experience it is totally absurd to think that you can just write "standards compliant HTML" and expect it to be rendered correctly on IE6 or 7 in any meaningful way anyway, you will always need to change your HTML and CSS to specifically support those browsers and realistically any browser that you want to support, the standards just are not uniformly implemented.