Meet the NoGray Color Picker.  It’s one of the most powerful color pickers I’ve yet seen due to its HSL support. (Thank You Mootools Color Plugin).  It’s also highly customizable to your projects since the widget interface is html based.

Also of note is its integration with input boxes.  The color of the input box background or a swatch next to the box can be controlled by the widget along with the hex value inside the box.

More info from the makers:
http://nogray.com/color_picker.php 

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