Specifically for you web designers out there, here is a handy built in Mac OS app that I didn’t know about until now. I was in search for a Mac alternative to Iconico’s Colorpic Tool (http://bit.ly/abxtW5) and happen to stumble upon the DigitalColor Meter app.
This tool does one thing, but does it really well. DigitalColor Meter will help you easily identify the exact RGB values for any pixel on the screen. I wish I had known about this ages ago. What a time saver! You can even copy and paste the exact RGB 8-bit HEX value for easy coding using keyboard shortcuts: Command-Shift-C
Here is where you can find DigitalColor Meter on your Mac: /Applications/Utilities
So go on, drag this little gem to your desktop dock for easy access.