Oh my, I love almost all poetry. It's hard to choose. If I had to pick one though it would be The Highwayman by Alfred Noyes:
The Highwayman
PART ONE
I
THE wind was a torrent of darkness among the gusty trees,
The moon was a ghostly galleon tossed upon cloudy seas,
The road was a ribbon of moonlight over the purple moor,
And the highwayman came riding