FaceTime was a welcome addition to iOS 4 though the downside was that it only worked over a Wi-Fi connection.
Well, iOS 6 undos that by adding cellular data support. Now you can use it on the road without worrying about hopping on a Wi-Fi connection.
Apple is also linking your phone number to your AppleID. This means that if someone calls your phone, you could actually answer it on your Mac or your iPad.