HueGo allows users to sample colors from their display or from a color prism. HueGo can be made to float in front of other apps by selecting "Sampler is Global" from the "View" menu.
Sample area is adjustable from 1 pixel to an 11x11 area
Color values can be quickly copied to the clipboard by clicking the "Go!" button.
The full version provides more options for editing and saving selected colors for future reference.