My editor of choice is Quanta+. It has all the features of a modern IDE, and really helps my productivity. It’s text editing capabilities alone (code completion, autocomplete, etc.) keep me hooked. However, if I’m in Windows, then I use my own editor, RingHTML 3.0, which I’m modeling on Quanta+.
Of course, the first additional tool I use is my browser, Mozilla Firefox. I write my sites too look perfect in Firefox, and then I adjust them for Internet Explorer. I’ve found this to be the most effective way of doing things. Generally (and this is a bit of a bit “generally”), if my sites work in Firefox, they work in Opera, Konqueror, and Safari as well.

Of course Firefox’s extension mechanism is ideal for extra tools right in the browser. Here are some of the extension I have installed, and which I use when developing site designs:

• Html Validator: Very handy, this extension validates your site without you needing to visit the validator at w3c.org.
• Aardvark: The Aardvark extension dynamically shows you all the elements, and their classes and id’s, when you hover over them.
• Web Developer Toolbar: Another absolute essential, you can do a multitude of things with this toolbar, including outlining of elements, viewing id’s and classes, etc.
• Fangs Screen Reader Emulator: This extension will pretend to be a screen reader, and will show you the output a screen reader would “say”. An almost must-have for accessibility.
• ColorZilla: Like that colour on a site you’ve seen? Grab it with ColorZilla.

Got any tools you use that you think are indispensible? Add your comment.