And, keep in mind that each of you can use one (or different) iTunes & App Store accounts, or take advantage of setting up multiple iTunes & App Store accounts using the same credit card - it's called Family Sharing, a new feature in iOS 8 - so you can set up individual iCloud accounts and keep the same music and app library.
On a Mac, you can also have multiple iTunes libraries on one Mac or PC - hold down the Option Key or Shift Key when launching iTunes and you'll get prompted to select or create a new library. You can also share or separate contacts into groups - so there will be four "me" people in your family...