Sorry, missed this
Apple "cut the cord" with iOS 5 and the introduction of iCloud back in 2011.
As of iOS 5, you no longer need to activate iOS devices using iTunes. They can be activated directly over 3G/WiFi.
You also no longer need to use iTunes for backups, as you can use iCloud instead.
Plus, you no longer need to use iTunes for iOS updates - iOS devices can be updated directly over WiFi without using iTunes.
Given that you can also download apps directly from the App Store app, music and videos from the iTunes app, and books from the iBooks app, you also don't need to use iTunes to add content to an iOS device either...
...Unless you want to add your own music library to an iOS device, but as Gary said there are also ways around that, by using an iTunes alternative.
Videos? If you use AVPlayer (iPhone) / AVPlayerHD (iPad), you can play a variety of video formats, including ones not supported by the native Videos app on iOS... And they can be added via a simple FTP transfer instead of an iTunes sync.