Features

Eyedropper - get the color of any pixel on the page
An advanced Color Picker similar to ones that can be found in Photoshop and Paint Shop Pro
Webpage Color Analyzer - analyze DOM element colors on any Web page, locate corresponding elements
Ultimate CSS Gradient Generator
Palette Viewer with 7 pre-installed palettes
Color History of recently picked colors
Displays element information like tag name, class, id, size etc.
Outline elements under the cursor
Manipulate colors by their Red/Green/Blue or Hue/Saturations/Value components.
Auto copy the generated or sampled colors to the clipboard in CSS RGB, Hex and other formats.
Keyboard shortcuts for quickly sampling page colors using the keyboard.
Get the color of dynamic elements (hovered links etc.) by resampling the last sampled pixel

Single-click color picking - click on the main ColorZilla toolbar icon and you're ready to pick (currently only available on Windows).
Pick colors from Flash objects
Pick colors at any zoom level

Install ColorZilla 2.0