Prince's Purple Rain

They filmed the movie to promote the album. The soundtrack was #1 on the Billboards for 24 straight weeks. It's what launched Prince to super-stardom.

Purple Rain was the album of the year and sold more than 25 million copies in the last 35 years. The accompanying (and pretty good) movie made 70 million dollars on a budget of 7 million. Prince won an Oscar for the Purple Rain OST.

New TV shows in 1984: Miami Vice, The Bill Cosby Show, Airwolf (Jan-Michael Vincent died just 10 days ago), Riptide, Murder She Wrote, Highway to Heaven.

Revenge of the Nerds is a classic!
Neverending Story is pure magic!
Police Academy, Red Dawn, The Last Starfighter, Dune, Breakin', Starman, all were huge parts of my childhood.

1984 was pure eighties bliss. Science Fiction, Fantasy, and Comedy had some of their greatest moments.

Beverly Hills Cop. What an intro that movie had! I think as a kid, the Detroit Police Chief was what I thought was the most funny. It's still maybe the movie I've watched the most in my life.

One of my favorite albums of all time and considering the fact that pretty much the entire casts except for a couple of people never acted in a movie before the movie is actually pretty good also.  

One of the better movies from 1984 and one of Eddie Grant's better songs.

Another good movie from 84 and if Purple Rain didn't come out that year it would have been the best movie soundtrack from 1984.

Paris, Texas
Broadway Danny Rose
1984
Amadeus
Once Upon a Time in America

On the lighter side Terminator, Ghostbusters, Gremlins, Indiana Jones and the Temple of Doom, Karate Kid (watched that with kids again not two weeks ago)

As far as instrumentals go Once Upon A Time in America was the best soundtrack of 1984 unfortunately it didn't get nominated for a Academy Award since the US version was severely shortened and they cut Ennio Morricone's name from the opening credits which disqualified it from being nominated but at least it won a BAFTA award for best Film Music.

Since nobody mentioned it 1984 also gave us one of the best mockumetaries of all time in This Is Spinal Tap.