The most untraditional princess fairytale romantic comedy ever backed by Disney, and the literal Godfather (Godmother?) of the genre. Made by Garry Marshall for $14M, brought in over $463M, and after half a dozen then-bigger stars passed on the script, 21-year-old Julia Roberts rocketed to superstardom, and into a nomination for Best Actress for this role. (We note that historically, if an actress wants an Oscar nomination or the actual award, she should play a prostitute. The tally bears this out time after time. Which says a lot about Hollywood one way or the other.)
And yes, the movie works because every woman who saw it wanted Richard Gere to drive up in a Lotus and offer them a ride, and every guy would love to own Julia Roberts for a week. But it also works because Marshall is a comedy directing maestro, Hector Elizondo nonchalantly and masterfully steals every scene he's in, Jason Alexander can be a good guy or a bad guy so well because he knows where the line is and when to push, and because everyone from Ralph Bellamy to the last one-line actor in the movie delivers top-notch performances right on cue. A title from the kickass song by Roy Orbison, and the song itself didn't hurt. And everyone likes a happy ending.