Internet Explorer is probably the worst browser out there among commonly used browsers. By commonly used browser I mean the following :

Internet Explorer 7
Internet Explorer 6
Firefox 2
Safari

Of course there are other rogue browsers that are rarely used, like Camino, Netscape, and some other nameless ones that most people do not know about, but the above 4 are the most frequently used browsers in the world right now.
Among all of them, Internet Explorer has, perhaps, the worst parsing and display system. It has problems with displaying PNGs (alpha layers will show …