For me, I think Jim and Pam would be at the top of the list. I still get very swoony every time I watch it and I've seen it a dozen times.

The Parent Trap bugs me. On the surface it's a cute movie, but in reality those folks are horrible, selfish people. Who gives up a baby just to not have to see a dude again? That's what custody battles are for! Those kids would need years of therapy. I still love the movie, I just have to severely suspend my disbelief to watch it.

You should watch Story of Us. It's also directed by Rob Reiner and has a great This Is Why I Love You speech.