So a good movie doesn't mean a good British effect. Be sure to find someone with relatively standard pronunciation. British sound is British sound and American sound is American sound. You can't mix them with others.
If you want to learn English sounds, you might as well try Love Actually, which is almost full of big-name actors, all of whom are relatively pure English sounds. And the movie itself is very interesting and relaxed. The English in the new Pride and Prejudice is too old. Roman Holiday is also good, but the film is a little old. Personally, I don't like black and white-of course, it's up to you.
If you want to learn American English, you can try American campus youth comedies such as Admission Notice, Superman College, Miracle Cinderella and Jump Out of My Life. The lines in this kind of movies are fashionable, accurate in pronunciation (you can call them that without personality) and entertaining.
If you want to learn more easily, you might as well watch some cartoons, such as Kung Fu Panda, Finding Nemo and Ice Age. These movies are all for children, with accurate pronunciation, relatively slow speech speed and strong entertainment.
Action movies. . . I recommend Nicolas Cage's con air. They are all classic (if you can tolerate BW). In fact, Cage also has many good-looking literary films, such as Family.
I think Saving Private Ryan and Gone with the Wind are better classics, depending on whether you like this genre or not.
Besides, if you want to know Black English, Jedi 1 2 is definitely worth seeing, believe me.
Finally, I recommend a movie I like very much: Love Holiday, with two English sounds, two American sounds, handsome men and beautiful women, and a big-name actor. An incurable romance. . .
Besides, some people may say, friend. Friends is an excellent American drama, and I like it very much, but in order to shape the characters, the actors in Friends except Rachel are either upside down, uneducated or have extreme pronunciation, which is not suitable for beginners like you. Besides, your major is spoken English, so it's better to wait until you have a certain foundation. Speaking of American TV series, I suggest you watch heroes. You can find the bilingual version of yyets on the electric donkey. The pressure of breaking out of prison is too great for our teacher. Of course, I also like Prison Break, but I just don't think it's suitable for your present situation.
In fact, after all this talk, you have to practice it yourself, just like a craft. No matter what you think, you won't do it yourself. It's no use watching too many movies without practicing.