When I was on Linux, I used a tool called KColorEdit. It was a standalone color picker that was part of KDE. It would allow me to input a hex color code, adjust via RGB or via HSV (Hue, Saturation and Value).
I was dismayed when I starting looking for a Mac equivalent. Most things I found fit one of two categories. They were either a plugin for something else or they were a “web safe” color picker. Now, sure many of the latter were old, but some were not. Web safe colors are so 1998.
I enlisted the help of some Mac friends. They pointed me here and there. I found a nice trial-ware application called Color Schemer. But, its $50. All I need is a color picker. They do have a cool web page though that lets you do some color matching.
Along the way, I also found a hex plugin for the Mac OS X color picker from Lucky Software. But, there seemed to be no way to invoke this from within jEdit.
Then, a buddy found this post on MacOSXHints. It describes how to make the OS X color picker into an application. W00T!!