In order to get IE to comply (and not do the terrible, horrible things IE 6/7 did), add this to the <head>:
<meta http-equiv="X-UA-Compatible" content="IE=8" />
It is great that Microsoft included this in IE8, but this can be a bear to update on every page. My workaround was to add this in the standard header information and use an include file for the <head> information.
