This post will contain spoilers for Roman Holiday, Notting Hill and Legally Blonde, although if you are worried about being spoiled for romcoms, I don't think you're quite getting the genre.
I hadn't realized until my current rewatching of Roman Holiday the extent to which it influences Notting Hill. Replace the princess with the film star, and there you have it. There's even the press conference set piece at the end. The main difference is that in the '50s Gregory Peck and Audrey Hepburn have to part. But by the '90s, Hugh Grant and Julia Roberts can be together. And that, o my sisters, is progress.
Both films also contain one of my favourite romantic narratives: rich girl and poor boy in love. This has something to do with reconfiguring patriarchy, I'm sure. You can join up the dots yourself.
I also thought as I was watching how much fun it would be to have a Bujoldian version of Roman Holiday. Gregor would be in the Audrey Hepburn role, of course, and someone like Elli Quinn would have to be in the Gregory Peck role. Of course, Bujold largely does this herself in The Vor Game, but it's all a lot more dramatic and serious in that, and without the romance. Something lighter and more comedic - and romantic - is what I had in mind. Still set in Rome, mind you.
While on the subject of romcom, my recent viewing of Legally Blonde brought home the extent to which the romance is actually between Elle (Reese Witherspoon) and Vivian (Selma Blair). They follow the classic romcom track: initial dislike and hostility, tentative and guarded overture, misunderstanding and massive fallout, ultimate reconciliation. Elle's romance with her professor, Emmett, has no real trajectory in comparison. In fact, all you need to do is replace the caption: "Emmett is going to propose - tonight" with "Vivian is going to propose - tonight", and you would have a genuinely perfect film. It's pretty damn close already.