Julieanne Kost, who is an outstanding Photoshop and Lightroom teacher, has a post on her Blog today about the changes to the Eyedropper tool in the new Photoshop CS5. When you click on an image with the Eyedropper tool it now displays a ring that shows you the color you are sampling in the upper half and the color before sampling in the lower half. They have surrounded the ring by an outer grey ring to help neutralize the surrounding colors. This is a really useful addition to Photoshop.