Mac OS X: Skitch is good software, and likely worth paying for in its 1.0 "Plus" edition. But if you were using Skitch long before the paid release, you can upgrade to a year of Plus capabilities for free.
Head to skitch.com/love, sign in with your email address and password provided by Skitch when you first signed up (or log in to share photos), and you'll be able to activate your Plus version. Simply restart Skitch on your Mac after that, and you're running with the ad-free, full-web-page-capturing, extra-tool-having Plus version. It's a nice reward for the beta base, and a good way to make sure you dig Plus' handy features before opening up the virtual wallet.