As has been said, the answer is going to depend on who you ask. This forum has participants from England and Canada and the US. I hope you will get a response from representatives of each of these places.
Also, if you ask high school teachers versus college instructors versus university professors, you may get three different answers based on what is en vogue at each level and what nation's literature offers the most richly appropriate body of instructional materials.
As an American interested in works from the 20th century, I prefer American literature over English lit and over Spanish language literature as well. However, I do read and intend to continue reading literature from around the world (in translation, I humbly admit).
But, if you'd like a categorical answer, it's my impression that Faulkner is still king of world literature and his second is Hemingway. This is said, of course, in consideration of Shakespeare as the most widely read writer of all time.
The writers of American modernism dealt with themes that still resonate today and, really, still seem like open (cultural) wounds, being taken up again by Coetzee, Morrison, and other contemporary writers around the world.