As officially announced just yesterday, Apple today has launched OS X Lion, which is now available [App Store] exclusively via the Mac App Store. Priced at $29.99, OS X Lion is Apple's next-generation operating system for the Mac platform. OS X Lion Server [App Store] is also available as a $49.99 add-on to the basic Lion install.
OS X Lion brings a number of new features to the Mac, including an iOS-like application launch screen known as Launchpad, full-screen apps, a new combined interface for Dashboard, Expose, and Spaces known as Mission Control, enhanced Multi-Touch gestures, and improvements to a number of core applications such as Mail.
Finally! I'm going to go upgrade now