To target elements only in IE browsers i\'ll use
IE6:
* html #nav li ul {
left: -39px !important;
border: 1px solid red;
}
I realize this is an old question but it was the first result on Google when I searched and I think I have found a better solution than the highest ranked suggestion and what the OP chose to do.
#nav li ul:not(.stupidIE) { color:red }
So technically this is the opposite of what the OP wanted, but that just means you have to apply the rule you want for IE8 first and then apply this for everything else. Of course you can put anything inside the () as long as it is valid css that doesn't actually select anything. IE8 chokes on this line and doesn't apply it, but previous IEs (ok I only checked IE7, I have stopped caring about IE6), just ignore the :not() and do apply the declarations. And of course every other browser (I tested Safari 5, Opera 10.5, Firefox 3.6) applies that css as you would expect.
So this solution, I guess like any other pure CSS solution would assume that if the IE developers add support for the :not selector then they will also fix what ever discrepancy was causing you to target IE8.