The old and painful problem with Internet Explorer is the PNG transparency. IE6 is still so wide-spread, damn. Few clever people created a JavaScript fixes for that. The best I know is iepngfix. It has a little limitation and works for IMG, background-image, …

Besides the PNG transparency Internet Explorer has many other holes. Missing CSS selectors, wrong box model, … I found IE7 script which patches most of those holes. So great! Now I can use selectors like DIV > DIV or DIV + DIV everywhere. It also fixes the box model (total width = margin + border + padding + width) and min-height/min-width. It tries to fix the PNG transparency too but it is not as well tuned as the iepngfix. You should remove this path of the script.