Haven't seen Stoner mentioned, which is widely held as a favorite classic. It was a darling last year with most of the book influencers (not sure why it became popular with them) and often lauded as people's favorite books ever up there with Lonesome Dove. I read it last year and enjoyed it as a lazy read on the beach type thing. Far from favorite books ever ever. Yes, the prose are outstanding and the story is told clearly by an expert, but the story itself is about as basic as you can get. Maybe that is why it is so heralded, he wrote a story about nothing that you don't mind reading.
As someone above said, I try to squeeze in a classic every so often. Count of Monte Cristo is next for me. Son read Crime and Punishment recently and made me add to my tbr list. Otherwise I've read most of the others sometime in my longer than should be life.