Apple introduced a new-look Mac operating system today, Mac OS X Yosemite. Here's a random sampling of the new look. We'll provide a link here later for a deeper dive and a full walkthrough of the system.
How notifications will look:
WWDC
It's called Mac OS X Yosemite:
Apple
Apple exec Craig Federighi introduced the new system:
WWDC
Note that the dock has lost its "shelf" look:
WWDC
Here's the email markup tool in action:
Apple