IE DOM Inspector

I hate Internet Explorer! I'm sorry for Microsoft guys, but it was a terrible pain to develop web pages/applications and make them compatible with MSIE and the primary browser I use (Firefox, of course).

This tool is to Internet Explorer like Firebug is to Mozilla Firefox (well, it's not SO complete and cool). We are talking about an essential application to empower the web developer with a large set of tools focused in the debugging phase of any web project.
IE DOM Inspector (now called IE Web Developer V2) is and add-on for Internet Explorer, you have to make it visible after installing it (IE7: Tools->Toolbars->Explorer Toolbar->IE DOM Inspector). You will see the add-on at the bottom of the browser window, showing you the DOM structure for the current document (with the ability to manipulate it on the fly, modifying and deleting elements) and the list of all included images, objects, and scripts. You can navigate through them, change its attributes, and much more.
It's very handy and simple to use.