Color Picker Pro

Pick single or multiple pixel colors anywhere on your screen in more than 25 formats with advanced and feature-rich color picker! The program supports picking colors from even dynamic content like DirectX.
Its built-in color converter lets you convert colors from one color model/space/format to another easily. Color Picker Pro supports: RGB, HSB, HSL, CMYK, CIE XYZ, CIE Lab, CIE Luv, LCH, Yxy, YIQ, YUV, YCbCr, YCC, YPbPr, Hexadecimal, Photoshop, OLE, HTML, VC++, Visual Basic, and many other color formats.
In addition, the program can automatically generate color variations for the colors you pick: complement, inversion, contrast, brighter, darker, grayscale, and many others.
Built-in zoom preview lets you magnify portions of your screen to pick the desired pixels right away. Color Picker Pro also gives you freedom over how you pick colors. Pick colors either by freely moving your mouse, or by first clicking and then dragging your mouse.
Overall, it is advanced and feature-rich screen color grabber.