In the latest Mac OS X 10.7 Lion Preview Developer Build, Apple has scrapped the switch/slider tabs that were borrowed UI elements from iOS.



From TUAW:

As you can see from the image above, Apple has chosen to move away from the Aqua interface of Snow Leopard (and previous versions of OS X) and moved towards a more toned-down appearance. When Lion Developer Preview 2 was released, Apple replaced aqua tabs with slider tabs. For example, in the second tab bar above, when the user clicked on "General" the white tab over "Privacy" would slide over to "General." This UI element can be found in many app settings in iOS (think of the familiar "ON/OFF" switches).

  Apple scraps iOS-like slider tabs in latest Mac OS X Lion build