A good journal. For prayers, poems, dreams, and secrets.
A passport. Because you never know when you'll need to go to Paris or Rome at a moment's notice.
One piece of special jewelry. It doesn't matter if it's a tin ring from a Cracker Jack box that your brother gave you at your first baseball game or a Tiffany necklace that your parents gave you at college graduation. What matters is that there is a special story behind it, one that is meaningful to you.
A really good hairdresser. Life is just too short not to have great hair.
Pride and Prejudice. Every girl needs to know Elizabeth Bennet.