I'll mention a few that have stood out to me recently.
Stoner, by John Williams. No, it's not about a stoner. It was written in the 60s, I believe, and concerns a down-and-out farm boy turned English professor. It's a wonderful character study of several people, especially the main character, who is quiet, troubled, inept, submissive and yet somehow noble. I was surprised that I found a book with so little plot to be so engaging. I picked it up because I was looking for modern classics that were relatively short. I thought it was great.
Revolutionary Road, by Richard Yates. Another fantastic character study, this one about a husband and wife, both struggling with "the American dream," image vs. reality. Yates has a fantastic ability to describe psychological states/dynamics from the inside. It was made into a movie, but there's no way the movie could do justice to the novel.
Way Station, by Clifford Simak. This is a science fiction novel, written in the 60s. I used to read SF when I was younger, but I never read any Simak. I missed out. He's good. Very clear prose, well paced story, good characters. More warmth and humanity that you find in most SF. The story concerns an ordinary man who lives in a house that functions as a way station for alien travel. The themes get larger as the story progresses, and it's both entertaining and emotionally satisfying in the end. I was surprised. I'm going to pick up his most famous novel, City, next.