I can't remember any flicks I saw before the reading books. The Bourne books were good as was the movie. I think the main character was fleshed out more in my mind than the movies had time to do.
Reading Elmore Leonard's books "Rum Punch" from which the movie "Jackie Brown" was taken and "Get Shorty" added a lot to the movies. Both flicks were different from the books but represented the books well in the basic characters.
Of course, my wife works in a book store and I commuted on the
Brem ferry for 71/2 years so I had time to read alot.