ColorZilla
… is an extension for Mozilla Firefox and the Mozilla Suite.
It assists web developers and graphic designers with color related tasks – both basic and advanced.
With ColorZilla you can get a color reading from any point in your browser, quickly adjust this color and paste it into another program. You can Zoom the page you are viewing and measure distances between any two points on the page. The built-in palette browser allows choosing colors from pre-defined color sets, saving the most used colors in custom palettes. DOM spying features allow getting various information about DOM elements quickly and easily

Portable Firefox 1.0 (USB Drive-Friendly)

Portable Firefox is a fully functional package of Firefox optimized for use on a USB key drive. It has some specially-selected optimizations to make it perform faster and extend the life of your USB key as well as a specialized launcher that will allow most of your favorite extensions to work as you switch computers.