Sip is a perfect example of the type of little tool that makes Mac OS X the best OS for designers. It's an absolute gem and there's simply nothing quite like it for Windows.
I've been a Sip user for a good time now. It's a great app that I can count on to hold and utilize my various clients' color schemes, etc. As a developer it's easy to "sip" colors with different color formats too. Lastly, they've always been responsive to my comments and questions on Twitter. Not too many developers do that. I highly suggest designers *and* developers to grab it.
Embark