Is it important to be able to see a live updating preview of tweaking palette colors?

I'm writing a pixel editor, and I want to build a kickass color picker and palette tool. But I'm pretty noob at actually pixelling, so I don't have a great feel for what's important in those tools.

I remember seeing a colour picker somewhere in which you would choose a colour, and it would show you the colour plus a couple of shades lighter, darker, redder, bluer and greener, but I haven't been able to find it.

Some references I've collected: http://hslpicker.com/, http://www.colourlovers.com/colors/add, and some more crazy stuff like http://www.colorotate.org/. I collected some assorted screenshots and more references: http://nornagon.net/color-pickers.html

As for organising palettes, I haven't really seen anything more than a list of colours. Would it be helpful to be able to organise a palette into a set of ramps? Is it nicer to organise it in a freeform way, like or (from Helm and Arne on this thread http://www.wayofthepixel.net/pixelation/index.php?topic=4306.0)?


How do you like to choose and organise your colours? Is there a particular tool you love to pieces? Is there something you wish you could do that nothing currently supports?

Ideas very welcome!

I'd like to try my hand at a walk cycle, but perhaps this particular character would actually run everywhere