I’ll admit that I pulled a fast one to exclude Cather from my list by referencing “more than 100 years ago,” and My Antonia was published in 1918. I think that’s the most canonical of her works, and I’m with @mamalion (and against my doppelganger, @mathmom) as to its quality. Also, @alh, Cather was way less dead-white-mannish than Wharton.
My mother’s high school American Lit curriculum included many of the books @mamalion cites. She adored Billy Budd. She had her students read London’s more-obscure Martin Eden, in part because most of them had read Call of the Wild in middle school. I’m sorry, though. Maybe it’s just the particular indoctrination I had, but I see Alcott and Lewis as of historical, not literary importance (although possibly important to the history of the business of literature), and Huckleberry Finn as important to the history and development of literature, although it’s not necessarily my favorite Twain.
Some of @mamalion 's post reminds me of a great scene in David Lodge’s first novel, Changing Places. The Berkeley English department plays a party game, where each person admits to not having read a particular book, and scores points based on how many of the other people have read that book. A particularly competitive young professor claims – falsely – never to have read Hamlet. (Not positive I am remembering correctly, and maybe it’s Romeo and Juliet.) He wins the game decisively, but is denied tenure the next day notwithstanding strong publications because everyone feels uncomfortable granting tenure to someone who has never read Hamlet. Really, @mamalion? No Dante and no Symposium? I’m not going to say you have to read Paradiso, but Inferno is really good. As is Symposium. Everyone reads them in large part because everyone likes them; they’re super enjoyable, and not that long, either.