That is a very hard question to answer. That's like asking "Who is the greatest basketball player ever?" Now, many, many, MANY Americans would say "Micheal Jordan", but I disagree. When I watch him play, he 'travels' according to the rules I was taught. He often would take 2-and-a-half steps when going up for a shot.
I'm not saying that is wrong or right - my point is that the game has changed so much. If you made him play with the same rules that they played under in the 60s, he'd never get a shot off.
Movies are the same way. "Citizen Kane" is often cited as the best movie ever. Part of the reason is that it was the first movie to use many techniques we take for granted now. Things like deep focus, set-pieces with ceilings, extensive use of flashbacks and alternate points-of-view are so common we're not even aware of them today, but in 1940, they were virtually unheard of.
so how do you compare a 70+ year old movie against more modern counterparts?
There are only two hard things in computer science: cache invalidation, naming things, and off-by-one errors
In 22,000 A.D., a ship carrying Paul Atreides arrives on the barren 'new world' of Arrakis. The colonists are mining for melange. Paul Atreides begins exploring the new territory, and encounters Chani. Initially, she is distrustful of him, but eventually overcomes her trepidation. The two begin spending time together, Chani helps Paul understand that all life is valuable, and how all nature is connected in a circle of life. Furthermore, she teaches him how to hunt, ride sandworms, and of her culture. We find that her father is a sort of adopted daughter of Stilgar, the Naib of Sietch Tabr. Over time, Paul and Chani find they have a love for each other.
There are many, IMO. 10 from the top of my head at the time of writing.
- Mr. Smith Goes to Washington (Jean Arthur played awesome. I first time felt that a Hollywood actress can be that good)
- Pulp Fiction (I like the idea of putting sequence in random order)
- God Father 1 (Of course)
- God Father 2 (I like Robert too)
- The Lord of The Rings - all 3 (Brilliant work)
- Being There (Peter Sellers played well)
- V for Vendetta (Remember remember ....)
- Sixth Sense (Love the ending)
- Shutter Island (DiCaprio is really a very good actor)
12 Angry Men, I will probably watch this weekend. Yeah, I know its too late.
My criteria for "best" (which is not likely to be your definition) includes:
1) concise: every scene, and every line is needed to tell the story, nothing can be cut out.
2) story: great story that we care about
3) acting: serious acting by all, leads, secondary, and even cameos
4) become part of the culture: are the lines, scenes, and ideas part of the culture 50 years later?
For example, Star Wars (1/4 Lost Hope) is part of the culture, references to any bad guy as Darth Vader, etc. But its too long, lots of the early development of Luke could be cut.
By my definition, Casablanca is the best. Well, the acting by Ingrid Bergman was not very good, but she is so nice to look at. Especially the #4 criteria. The cantina scene in Star Wars was a direct reference to Rick's Cafe in Casablanca, and Jabba the Hut is Signor Ferrari, More so, when a politician is found to be crooked, or sleeping with his secretary, we are all shocked.