My current favorite from poetry:

  It may be that the gulfs will wash us down;
  It may be we shall touch the Happy Isles,
  And see the great Achilles, whom we knew.
  Tho' much is taken, much abides; and tho'
  We are not now that strength which in old days
  Moved earth and heaven, that which we are, we are,--
  One equal temper of heroic hearts,
  Made weak by time and fate, but strong in will
  To strive, to seek, to find, and not to yield.

  from "Ulysses" by Alfred Lord Tennyson

My favorite quote:

"All men dream, but not equally. Those who dream by night in the dusty recesses of their minds, wake in the day to find that it was vanity: but the dreamers of the day are dangerous men, for they may act on their dreams with open eyes, to make them possible."

-T.E. Lawrence