Pixie; a color picker made especially for webmasters and designers, is one of the tools I use alot when designing blogs and websites. It allows me to easily work with colors when working on html or css templates.
If I need to know the hex, RGB, HTML, CMYK and HSV values of any color, all I do is run the application and point it to the color. It is a color picker with few extra goodies which also shows the current coordinates of your mouse pointer.
If you know any alternative free color picker, kindly share it via the comment form below.