<!doctype html>
<html>
 <head>
  <title>IE10/11 Media Query Test</title>
  <meta charset="utf-8">
  <meta http-equiv="X-UA-Compatible" content="IE=edge">
  <style>
    @media all and (-ms-high-contrast:none)
     {
     .foo { color: gold} /* IE10 */
     *::-ms-backdrop, .foo { color: pink} /* IE11 */
     }
  </style>
 </head>
 <body>
  <div class="foo">Hello World</div>
 </body>
</html>

 

In the light of the evolving thread, I have updated the below:

IE 11 (and above..)

_:-ms-fullscreen, :root .foo { property:value; }

IE 10 and above

_:-ms-lang(x), .foo { property:value; }

or

@media all and (-ms-high-contrast: none), (-ms-high-contrast: active) {
   .foo{property:value;}
}

IE 10 only

_:-ms-lang(x), .foo { property:value\9; }

IE 9 and above

@media screen and (min-width:0\0) and (min-resolution: +72dpi) {
  //.foo CSS
  .foo{property:value;}
}

IE 9 and 10

@media screen and (min-width:0\0) {
    .foo /* backslash-9 removes.foo & old Safari 4 */
}

IE 9 only

@media screen and (min-width:0\0) and (min-resolution: .001dpcm) { 
 //.foo CSS
 .foo{property:value;}
}

IE 8,9 and 10

@media screen\0 {
    .foo {property:value;}
}

IE 8 Standards Mode Only

.foo { property /*\**/: value\9 }

IE 8

html>/**/body .foo {property:value;}

or

@media \0screen {
    .foo {property:value;}
}

IE 7

*+html .foo {property:value;}

or

*:first-child+html .foo {property:value;}

IE 6, 7 and 8

@media \0screen\,screen\9 {
    .foo {property:value;}
}

IE 6 and 7

@media screen\9 {
    .foo {property:value;}
}

or

.foo { *property:value;}

or

.foo { #property:value;}

IE 6, 7 and 8

@media \0screen\,screen\9 {
    .foo {property:value;}
}

IE 6

* html .foo {property:value;}

or

.foo { _property:value;}

Javascript alternatives

Modernizr

Modernizr runs quickly on page load to detect features; it then creates a JavaScript object with the results, and adds classes to the html element

User agent selection

Javascript:

var b = document.documentElement;
        b.setAttribute('data-useragent',  navigator.userAgent);
        b.setAttribute('data-platform', navigator.platform );
        b.className += ((!!('ontouchstart' in window) || !!('onmsgesturechange' in window))?' touch':'');

Adds (e.g) the below to html element:

data-useragent='Mozilla/5.0 (compatible; M.foo 9.0; Windows NT 6.1; Trident/5.0; SLCC2; .NET CLR 2.0.50727; .NET CLR 3.5.30729; .NET CLR 3.0.30729; Media Center PC 6.0; .NET4.0C)'
data-platform='Win32'

Allowing very targetted CSS selectors, e.g.:

html[data-useragent*='Chrome/13.0'] .nav{
    background:url(img/radial_grad.png) center bottom no-repeat;
}