The best love poems ever?

My personal favorite is Sonnet XLV by Pablo Neruda. It's beautiful in Spanish and, remarkably, is a poem that does not lose any sentiment in translation to English:
 

Don't go far off, not even for a day, because--

because--I don't know how to say it: a day is long

and I will be waiting for you, as in an empty station

when the trains are parked off somewhere else, asleep.

Don't leave me, even for an hour, because

then the little drops of anguish will all run

together,

the smoke that roams looking for a home will drift

into me, choking my lost heart.

Oh, may your silhouette never dissolve on the beach;

may your eyelids never flutter into the empty

distance.

Don't leave me for a second, my dearest,

because in that moment you'll have gone so far

I'll wander mazily over all the earth, asking,

Will you come back? Will you leave me here, dying?