Recently I've been using grunt-modernizr, which is pretty fantastic as it can be set to build a modernizr js file based on the classses that appear in your CSS or JS, as I've been trying to move away from HeadJS. While this post might be a bit antithetical to the point of Modernizr, there are plenty of reasons why to detect IE versions

IE version Test Class
IE8 and below csstransforms3d .no-csstransforms3d
IE9 and below subpixelfont .subpixelfont
IE9 only csstransforms3d subpixelfont .no-csstransforms3d .subpixelfont
IE10 and below borderimage .no-borderimage
IE10 only flexbox .flexboxtweener
IE11 only borderimage .borderimage

Note: borderimage, csstransforms3d are a core detect. Please note these detects are not IE exclusive.