Color Picker ColorZilla Is my "color picker" of choice for use in skin design. It is available for free as both a Chrome and Firefox browser extension.
In skin design, I use both the single point and 3x3 avg eyedropper to find colors that match other elements of the skin instead of having to second guess what works and what doesn't.
Do you use or need a color picker? This picker is one of the best on the web.