Web designers and programmers who need to specify colors must use a special code. This code can amazingly in this day and age not be found directly within the Mac OS X color panel. Launching other applications just to calculate it is tiresome and unnecessary.
Hex Color Picker puts an extra tab in the system-wide color panel. Instantly see the hex color code for any color, and edit it just the same with a number of shorthands.
Hex Color Picker has some shorthands for entering the hex color code quicker - deductions for the full 6 digit string from 1, 2 and 3 digits alone, knowledge of HTML/CSS color keywords (like orange, hotpink or chartreuse) and live preview of the color as you enter its code. You can also tell it whether you'd like upper case or lower case letters.