I have two votes for most romantic movie of all time:
Heaven Can Wait (Ernst Lubitsch, 1943)
-and-
A Matter of Life and Death (Michael Powell & Emeric Presburger, 1946)
Maybe there's something about wartime which brings people's hearts out into the open.
Heaven Can Wait was filmed during WWII, but makes no reference to it whatsoever. It's the story of Ladies' Man Henry Van Cleeve (Don Ameche), who, upon his death, presents himself to His Excellency (Laird Cregar) at the Gateway to Hell. The Lord of the Underworld isn't quite ready to admit him when Henry tells him that his "life was one continual misdemeanor". At this point, Henry relates his life story, which mostly revolves around the women. Henry was always precocious, so his mother, grandmother, nannies and little girls all fought over him, ever since an early age. But it's only after he meets the lovely fiancee, Martha (Gene Tierney), of his cousin Albert (Allyn Joslyn), that Henry's heart feels something stronger within him for the fairer sex. With the help of his feisty Grandpa (Charles Coburn), he basically steals Martha and begins a lifetime love affair with her, even though he continues to have a weakness for the other ladies.
This film is definitely one of the funniest I've ever seen, and it obviously presents a totally believable loving relationship in the midst of a few which aren't quite so perfect. My point is that anything so honest and loving which can be so hilarious is a treasure to be cherished. It not only depicts passion but something more eternal.
A Matter of Life and Death is just as unique as
Heaven Can Wait. Coincidentally, it begins in what seems to be the lead character's death. David Niven is a pilot named Peter of a WWII RAF bomber on fire, with all others on board dead; he has no parachute, and he comes in radio contact with American WAC June (Kim Hunter), stationed in England. As he contemplates and explains his death to June, Peter falls in love with her, and unsurprisingly, she falls for his poetry and bravery in the face of certain death. The thing is, that as his plane is coming down over the coast of England, Peter jumps out but seems to survive. Not only that, he lands very close to where June works and meets her within five minutes of being shocked to find that he's not in Heaven, but still on this Earth.
June has a good friend in Dr. Frank Reeves (Roger Livesey), a brain surgery specialist, who tries to help Peter in every medical way possible. Although there is no rational explanation for Peter being alive after jumping, Frank tries to cure him of his dementia, which involves the fact that a heavenly conductor (Marius Goring) missed Peter in the English fog but wants to collect him now and take him to the Afterlife. June and Frank do everything they can to try to keep Peter alive and away from the Afterlife, even though Peter is convinced that his case is going before a Heavenly Court. What happens next is unbelievably perfect, even if my wife is heartbroken about one detail.