The “rule” that a preposition should not end a sentence goes back to the 18th century, when some grammarians believed English should bend to the rules of Latin grammar. But like the spurious prohibition against starting sentences with conjunctions, this rule goes against the glorious flexibility of English and often leads to unnatural-sounding sentences.
Ending sentences with strong words is a good idea, but not when it means contorting the language away from natural expression. Winston Churchill (or someone else—the quote has been attributed to many people) provided the best rejoinder to this rule. When criticized for ending a sentence with a preposition, he replied,
That is the type of arrant pedantry up with which I shall not put.
Yet the phony rule lives on as an illogical superstition throughout the English-speaking world. As a result, while reorganizing sentences to avoid terminal prepositions sometimes has lovely results, we also get stilted sentences like these:
It was my mother about whom we were most concerned. [Chattanooga Times Free Press]
Red snapper, the one with which I am most familiar, is primarily an Atlantic fish … [Marco Island Sun Times (article now offline)]
Now it remains for us to decide how we will live and for whom we would die. [Green Bay Press Gazette (article now offline)]
California is a place across which you drive but never quite feel a part of. [New Statesman]
(That last one is particularly hard to explain.)
As with many grammar and usage rules, the question of whether or not to end sentences with prepositions is ultimately a matter of taste. Some readers might think the above examples sound better than the alternatives with sentence-ending prepositions. Neither choice is correct or incorrect.
Great writers have never been hampered by these arbitrary rules, and sentence-ending prepositions can be found in some of the most beautiful writing in the English language—for example:
I say you shall yet find the friend you were looking for. [Walt Whitman]
Mrs. Bennet had many grievances to relate, and much to complain of. [Jane Austen]
The domestic man, who loves no music so well as his kitchen clock and the airs which the logs sing to him as they burn on the hearth, has solaces which others never dream of. [Ralph Waldo Emerson]
Then she remembered what she had been waiting for. [James Joyce]
Mr. Barsad saw losing cards in it that Sydney Carton knew nothing of. [Charles Dickens]
Finn the Red-Handed had stolen a skillet and a quantity of half-cured leaf tobacco, and had also brought a few corn-cobs to make pipes with. [Mark Twain]
There was a little money left, but to Mrs. Bart it seemed worse than nothing””the mere mockery of what she was entitled to. [Edith Wharton]