PK's Color Picker

PK's Color Picker is a lightweight freebie that allows users to pick a color from the screen and get the RGB values in a second.
It's all a very user-friendly environment, although you may find the interface a bit cluttered at the first sight. Options are all grouped in a single screen, so it's only a matter of time until you get used to it.
A zooming panel helps you select a specific color easier, while dedicated decimal, color and greyscale fields provide more information on the clicked color.
The application relies on a fairly easy to understand procedure that's also detailed in the help section. Simply launch the application, move the mouse cursor over the color you wish to pick and press the “Space” button on your keyboard.
PK's Color Picker instantly locks the color and displays the appropriate values in the main window. By default, the GUI remains always on top, but this option can be easily disabled from the same window.
There are no other configuration settings and one of the setbacks is that PK's Color Picker cannot be minimized to Tray for later use. It can run below the other windows, which is indeed a decent alternative, but a dedicated option to be minimized to Tray could come in much handier.
It doesn't really matter which Windows version you're running because PK's Color Picker gets along very well with all of them, obviously without requiring administrator privileges.
As a conclusion, PK's Color Picker is a decent application that relies on an interesting mix of features, all grouped in just one screen. Although there's no comprehensive help manual available, the program is aimed at all user categories out there.