Hadn't heard it attributed to Dryden before. Anyway, the irony of the whole preposition at the end of a sentence thing is that in PIE prepositions were probably postpositions, coming after the noun, as was still posssible in Vedic Sanskrit. In Sanskrit and Greek preverbs (which look a whole lot like prepositions) could separate from the verb (called tmesis in Greek, from the same stem as atom). In Latin, they're fused to the verb, so Dryden or whoever's analogy was specious indeed. One of the beautiful things about Latin, as well as many other inflected languages, is that word order can be played around with, words ending up all over the phrase / sentence because you can sort out the meaning via the case endings and meaning.

PS, I've also heard the anecdote that a secretary had corrected one of Churchill's speeches pointing out that a preposition should never occur at the end of a sentence. He replied in writing, "This is a rule up with which I shall not put."