I do quite a lot of futzing around developing web apps, and as a result I'm often needing to choose colours to use in them, and I want those colours in HTML hex form – e.g. #ff0000 (bright red). The standard Mac OS X colour picker is a pretty reasonable colour picker, with all the features I want: colour wheel, RGB sliders, HSB sliders etc. but it lacks the most crucial feature – easy output of HTML hex codes! This is clearly a criminal omission, and it meant I'd frequently have to convert from RGB 0-255 numbers down to hex, which is tedious in the extreme.