WARNING MAJOR SPOILERS
Me and You and Everyone We Know was pretty romantic throughout, but the ending especially...a very sweet movie.
Nightmare Before Christmas is an obvious choice. ^___^
Unleashed...maybe not traditionally romantic in the lovey dovey sense, but after all that brutality, to finally see those characters finding happiness and entering a new life in one piece is just such a relief that to me it couldn't feel more romantic. It's hard to explain how, you'd have to have seen the film.
Ditto for A.I...though its a much sadder case.