IE 6 and below
* html {}

IE7 only  

* + html .element {  margin-bottom: 10px;  }
IE 7 and below
*:first-child+html {} * html {}


IE 7 only
*:first-child+html {}


IE 7 and modern browsers only
html>body {}


Modern browsers only (not IE 7)
html>/**/body {}


IE 7
html > body #ie7 { *display: block; }

IE 6
body #ie6 { _display: block; }



IE8 Standards-Mode Only:

.test { color /*\**/: blue\9 }


All IE versions, including IE8 Standards Mode:

.test { color: blue\9 }

For Example code using hacks:

margin-top:10\9; for IE8
* margin for IE7 , IE6
* html margin and _margin for IE6