A couple of my favorites are from Dr. Seuss. One I actually put on a picture that I painted for Miles after he was born. "Today you are You, that is truer than true. There is no one alive who is Youer than You." It's now hanging in a frame in his room! :)
Another one is "You have brains in your head. You have feet in your shoes. You can steer yourself any direction you choose. You're on your own. And you know what you know. And YOU are the one who'll decide where to go..."
These are a good boost to remind me that my destiny is in my own hands and that being me is good enough! :)