Pickr

Pickr is a remarkably small, lightweight, and versatile color picker application that can be used by designers and developers alike.

Pickr sits in the background and is there when you need it. Just open Pickr's panel, right-click on a swatch and a magnifying loupe will pop open. The color can be automatically copied to the clipboard in a format of your preference.
Features:
- Magnifying panel to accurately grab the color of a single pixel
- Instant one-click color copy
- Copy color in a variety of formats (including Hex, RGB, NSColor and UIColor)
- Auto copy color to clipboard after selecting
- Simple right-click to grab a color