and not so popular, not all people would know. Like most people would say Titanic, notebook, Casabrance, not like that, not famous ones.
I love romantic movies and I own lots of random ones. Just to name a few/a lot 
….. 10 things I hate about you (Heath Ledger, Julia Stiles), 13 Going on 30 (Jennifer Garner, Mark Ruffalo) A cinderella story (Hillary Duff, Chad Michael Murray), August Rush (Keri Russell, Jonathon Rhys Meyers), Because I said so (Mandy Moore, Diane Keaton), Catch and Release (Jennifer Garner), Down to You (Freddie Prinze Jr., Julia Stiles), Elizabethtown (Kirsten Dunst, Orlando Bloom), Ella Enchanted (Anne Hathaway, Hugh Dancy), Failure to Launch (Matthew McConaughey, Sarah Jessica Parker), Get Over It (Kirsten Dunst, Ben Foster), Hitch (Will Smith, Eva Mendes), How to Lose a Guy in 10 Days (Matthew McConaughey, Kate Hudson), It’s a Boy Girl Thing (Kevin Zegers, Samaire Armstrong – so cute, similar to freaky friday), Just Like Heaven (Reese Witherspoon, Mark Ruffalo), The Lake House (Keanu Reeves, Sandra Bullock – phenomenal romance movie), A Lot Like Love (Amanda Peet, Ashton Kutcher), Love and Basketball (Sanaa Lathan, Omar Epps), Miss Congeniality (Sandra Bullock, Benjamin Bratt), Must Love Dogs (Diane Lane, John Cusack), No Reservations (Aaron Eckhart, Catherine Zeta-Jones), One Fine Day (George Clooney, Michelle Pfeiffer – love this movie!), Penelope (Christina Ricci, James McAvoy), Picture Perfect (Jennifer Aniston), The Prince and Me (Julia Stiles), Save The Last Dance (Julia Stiles, Sean Patrick Thomas), She’s All That (Rachel Leigh Cook, Freddie Prinze Jr.), She’s The Man (Amanda Bynes, Channing Tatum), Sleepless in Seattle (Tom Hanks, Meg Ryan), Sweet Home Alabama (Reese Witherspoon, Josh Lucas), The Wedding Date (Debra Messing, Dermot Mulroney), What Happens in Vegas (Cameron Diaz, Ashton Kutcher), When Harry Met Sally (Billy Crystal, Meg Ryan), Win a Date with Tad Hamilton (Topher Grace, Josh Duhamel, Kate Bosworth), You’ve Got Mail (Tom Hanks, Meg Ryan)
Source:
http://www.somethingaboutw.org/cameron-diaz-pictures/what-are-the-romantic-movies-that-are-not-famous