Recently came back to the Mac world after years away. My wife and I plan on using the Mac for personal use and business use and would like to setup various accounts on the computer. What I was thinking was an account for myself, an account for my wife, one for the business (each of us having access) and on account for the kids. Now my questions; 1) By using accounts will we each end up with our own iPhoto and iTunes libraries? If so can we move photos and music from one account library to the other account library easily? 2) I understand Time Machine can backup the entire internal HD or selected items. Can you set it up to back up by accounts? Say just mine, my wifes and the businesss accounts? 3) By using different accounts do you reduce the efficiency of the HD? In other words do you end up using more disk space this way?