So if you've seen any of the Blu-Ray movies on a 1920x1080 HD display most of them look like this:
Some movies were filmed at something close to 1.77 times as wide as they are tall, but it seems to me that almost all of the movies I looked at do the black bar thing as above.
So it would be nice to have a screen that has 2.4 times as many pixels horizontally as vertically to watch all of these movies. But then I got wondering what the ideal resolution would be to capture all the detail present on the film that they recorded the movie on.
I came up with 6570x2740! This is because it turns out that 35 mm film has just about 5000 dots per square inch making up the picture... and they use about 72% of an inch to make most 2.4 aspect ratio movies (Super 32 filmstock), which comes out to 18 megapixel, which in the correct aspect ratio gives 6570x2740.
So yeah digital technology has a way to go before it can reproduce accurately what you see in the theater.