Well, depending on your intentions. The Notebook, Before Sunrise, Before Sunset...these are great movies.
Romantic movies are great, but if you want to watch an unconventially romantic movie, that also gets her ridiculously turned on, watch: The Girl Next Door. I think it accesses a hidden desire to be sexually liberated and in love.
I keep seeing a lot of repeating movies with good reason. But one you might not have heard of as much is "Chocolat" year 2000 with Jonny Depp and pretty Girl.
Ghost - The Notebook - The Lake house - Sleepless in Seattle - Up close and Personal - Note in a Bottle - From Here to Eternity - that should kill a rainy weekend --