I've chosen mine from C.S. Lewis' The Four Loves, a book I'm using extensively for my thesis.
“Friendship is unnecessary, like philosophy, like art, like the universe itself (for God did not need to create). It has no survival value; rather it is one of those things which give value to survival.”
And for our class quote we've chosen:
“Remember that when you leave this earth, you can take with you nothing that you have received-- only what you have given.” ~St. Francis of Assisi