HSI ColorChooser
Find a color in three ergonomic panels: hue, saturation and intensity
...This tool presents the HSI space in three cross sections maintaining one of these parameters at a constant value, keeping into account that, on RGB monitors, not all colors can be achieved with arbitrary pureness and lightness. On tuning H, S or I, the colored surface varies in shape accordingly.
Functions: hue, saturation and intensity controls, copy & paste RGB (decimal and hexadecimal) values, selected color preview, paste color