I have found the following books, or series of books immensely enjoyable.

C.S. Forester's "Horatio Hornblower" novels. I think these are better than O'Brian's books. Forester can tell a better story in fewer words.

Robert B. Parker's "Spenser" series of detective novels. Spenser was an erudite tough guy.

"Killer Angels" by Shaara.

"Bridges of Toko-Ri" by Michener.

"A Soldier of the Great War" by Helprin.

"The Princess Bride" by William Goldman. Better than the movie.

"To Kill A Mockingbird" by Harper Lee.

"The Life and Times of the Last Kid Picked" by David Benjamin. Not a novel but the story of growing up in WI; as good as the title is clever.

"The Hunters" by James Salter.

"The Cruel Sea" by N. Monsarrat.

"The Caine Mutiny" by Wouk.