The lock screen has been updated, getting rid of the glossy bits. Going with the rest of the interface, the lock screen is flat, and has live wallpaper animations. The rest of the home screen will have completely flat icons, and iOS 7 will take advantage of every pixel, from edge-to-edge.
The stock apps get rid of the skeuomorphic interfaces, and has new typography and gorgeous new flat interfaces. There are also new gestures that make it easier than ever before to interact with your apps.