I've heard "Crossing the Bar" by Tennyson put to music by Rani Arbo, and "Silence or Tears" by Lord Byron put to music by (maybe) Norman Blake. I'd be interested to hear tunes for some of Yeats' poetry.

One of his poems that impressed me greatly, the last lines of which still stick in my mind, is "The Second Coming," which ends with "What rough beast, its hour come round at last, slouches toward Bethlehem to be born?"

I've known people who spent years studying Yeats. Good luck!