I'm recieving my first macbook pro next week. I am about to order a Hitachi 7k500 or seagate momentus Xt (please help me choose here It will probably be the first thing I do when I recieve my macbook pro(if I have the patience to not start doing things on it). Do I start it up first or just immediatly change it. And do I have to back it up even if I haven't done anything on it yet? or will I otherwise lose stuff? please just some advice, and if I do have to back it up, what program should I use?