Aristotle on Friendship

But the complete sort of friendship that is between people who are good and are alike in virtue, since they wish for good things for one another in the same way insofar as they are good, and they are good in themselves. And those who wish for good things for their friends for their own sake are friends most of all, since they are that way for themselves and not incidentally; so the friendship of these people lasts as long as they are good, and virtue is enduring. (from Nicomachean Ethics, 1156B)

My four year college roomie and me, senior year, study break; next month, I'm having a baby and she's moving to Scotland for grad school - she is the best kind of friend a person can ever have.