This was immensely difficult to narrow down, so I have 20 Honorable Mentions this time!
I took into account each song's cultural significance, significance within the movie itself, vocals, and memorability. Also, I plan on doing a Best of Film Dances/choreography list later on, as well as a Best Film Scores list. Therefore, instrumentals are not included here, and that may also explain why memorable dance sequences aren't listed. There are way more than 100 that tick all of these boxes, and I made sure to do as much research into movie songs as possible, from AFI's 100 Years 100 Songs list and its 400 nominees to researching global cinema.
What's YOUR favorite song in movies?