this forum is older than i am so i will stick to modern.
mum and i watched and my faves from the hollywood era.
casablanca
gone with the wind
rear window
to catch a thief
psycho
I started with IMDb’s 250 Most Popular list and pruned it down to 20 finalists, knowing that certain personal favorites would be missing. But Crash and Snatch are both missing from the IMDb Top 250? :smack: Come on.
To cut it down to just five, I decided to allow only one Godfather flick, only one Bogart, only one Jack Nicholson (this was the unkindest cut) and only one Coen Brothers
Casablanca
Godfather
Fargo
Crash
One Flew Over the Cuckoo’s Nest
Birth of a Nation, Citizen Kane, The Godfather, Star Wars, and Toy Story. Not my favourites, but IMHO the five most important.
Dr. Strangelove
Sense & Sensibility/Persuasion (1995)*
2001: A Space Odyssey
Gallipoli
Rebecca
*disclaimer for two in one cheat
Some most-watchable choices:
Groundhog Day
Roxanne
Back to the Future
Peggy Sue Got Married
Which Crash are you talking about?
5 is so hard, I think I need a top 100. Leaving Young Frankenstein, Blazing Saddles, Monty Python and the Holy Grail, Airplane, Godfather II, Star Trek IV (The Whale Movie), Jaws, Indiana Jones and the Last Crusade, Aliens, Blues Brothers, Animal House, Local Hero, My Favorite Year, African Queen, To Kill a Mockingbird, Singing in the Rain, West Side Story, Fiddler on the Roof, Groundhog Day, Back to the Future, Up!, Shawshank, Pulp Fiction, Gump, League of their Own, Rocky, Goodfellas, Citizen Kane, Bringing Up Baby, Roman Holiday, Sabrina, Key Largo, Miracle on 34th Street, Mary Poppins, Wizard of Oz, Harvey and especially Arsenic and Old Lace and Ghostbusters off the list is painful. In fact Princess Bride was a die roll with the last 2.
ETA: Oh man, also the The Hudsucker Proxy and Josey Wales etc.
So-o-o-o-o, you are a fan of L.A. Confidential, huh?
BTW, I am not one to call another persons opinion wrong, you know De Gustibus and all that, but you folks who are putting Blazing Saddles on your list instead of Young Frankenstein are quite simply wrong,wrong wrong.
Crash (2004) with Don Cheadle, Sandra Bullock, Matt Dillon. Great film; one reason Cheadle is one of my favorite actors.
I’d never heard of Crash (1996) until you asked. That you imply it’s a plausible Top 5 candidate makes me intend to watch it soon! 
Big Trouble In Little China
The Fall
…I’ll have to think on the final three.
FWIW (and absent any tabulation error) here are the SDMB Top 23 through post #70
16 Casablanca
14 Godfather
7 Raiders of the Lost Ark
6 Dr. Strangelove
5 2001: A Space Oddysey
5 Goodfellas
5 Singing in the Rain
4 Blade Runner
4 Bridge on the River Kwai
4 Citizen Kane
4 Jaws
4 Memento
4 Pulp Fiction
4 The Princess Bride
4 Third Man
3 Aliens
3 Chinatown
3 Fight Club
3 Gone with the wind
3 Incredibles
3 Lawrence of Arabia
3 Raising Arizona
3 Star Wars
In no particular order:
Blade Runner (Final Cut)
The Grey Fox
Harvey
One Flew Over The Cuckoo’s Nest
The Secret In Their Eyes
Do so. It’s as good as they say.
I came so close to making this one of my five. (“Son of a bitch must pay.”)
To Kill a Mockingbird
The Lion in Winter
A Man for All Seasons
Fargo (but could be any of the Bros.)
The Usual Suspects
Casablanca
Young Frankenstein
One Flew Over The Cuckoo’s Nest
…and too many more…
Back to the Future
Singin’ in the Rain
The Princess Bride
Double Indemnity
Memento
The first four were pretty easy choices… the fifth was really a tossup. Could have picked any number of things.
Yeah. Picking just five is unrealistic.
A Man For All Seasons
Dr. Strangelove
2001: A Space Odyssey
Becket
Fantasia
Heh. Me too. That and the Kurt Russell version of, “The Thing.” Love them both dearly. I’d have to give “Big Trouble in Little China” the edge, though, as it just makes me so happy. . .AND it’s so quotable!
Not sure why these are all 90’s movies, but
Goodfellas
The Usual Suspects
L.A. Confidential
The Matrix
Army of Darkness
Little Big Man
The Life and Times of Judge Roy Bean
Romancing the Stone
Raiders of the Lost Ark
Return of the Jedi