What is a good small tattoo design for a girl on the neck or behind the ear?

I want to get a tattoo on the back of my neck, under my hairline or behind the ear. Something small and simple. I'm going away for college and want something that symbolizes my mom my sister and I. I was thinking something like a sun/moon and a star or a crescent moon and two stars. Any ideas? or pictures of some nice designs? I'm looking to keep discreet nothing too big.
I do like the idea of crescent moon and two stars. That style has held it's own for many years, and can be very feminine. There are so many artists with different styles out there that you can still get something rather unique. I would rethink putting in on your neck or behind your ear, however. From experience, I know that something on the back of the neck can be hidden by hair, but you may for some unseen reason years in the future have reasons to have to cut your hair off. Illness, accident, who knows. Then all of a sudden the tattoo that was hidden cannot be hidden. And if it's really important to you, i think you should get something a little bigger in a less conspicuous place. If not, I have seen more and more people getting tattoos on their earlobes, which in the event of interview or court or whatever, you can wear earings that will cover them up.