ColorMatch Remix This online tool allows you to pick a color and have several colors generated to match it. You can export your palette as a Photoshop or Illustrator file.
ColorPicker This color picker allows you to pick colors from photos and other images. It can ouput colors in either RGB mode or hex, which is useful for us CSS designers.
AllChars Ever had trouble remember that “&” should be “&” in HTML? AllChars will help you encode ANY character you want.
CSS Creator Use this online tool to generate the framework for your CSS based layout.
Firdamatic Another online CSS layout generator that can be used for either 2-column or 3-column layouts.
Helpful Firefox Extensions
Web Developer Toolbar for Firefox This plugin is a must have for any CSS designer. It allows you to view the CSS for a page, turn off styling and browse through the DIVs to see how a page is assembled.
IE Tab Check your website in Internet Explorer by opening it in a Firefox tab. Never open Internet Explorer again!
HTML Validator Adds a small section to the status bar displaying whether or not a website has valid markup. It even shows how many errors are in the site.