Of ~200 books I've read, the few that stayed with me over time and I find myself often thinking back to or referring to, in ~random order:

All short stories by Ted Chiang, especially Exhalation, Division By Zero, Understand, The Story of Your Life, Liking What You See, The Lifecycle of Software Objects, What's Expected of us, just excellent themes ideas and reading all around.

The Selfish Gene (nonfiction) - a classic for understanding evolution and natural selection, especially the realization that the gene is closer to the real unit of selection more than an individual, explaining altruism and colonies and a lot more.

The Lord of the Rings (fantasy) - I return to LoTR all the time for comfort. I don't think anyone else has created a high fantasy Universe this complex, with so much mythology, symbolism, new languages, mysterious system of magic, ancient and powerful beings and artifacts, beautiful writing and dialog, themes of courage, friendship and heroism, the list goes on and on... You're thrown into a world with characters and references to so many things that are part of this ancient world and never really introduced. There's always more to find on each reading.

The Martian (~scifi) - top tier science porn, competence porn, fast paced and fun.

The Vital Question (nonfiction) - First time I intuitively grokked the bridge from geology to biology, the origin of life, and likelihood of life in the Universe at large at various stages of complexity and development. Also all other Nick Lane books.

How To Live by Derek Sivers (nonfiction) - 27 conflicting answers to how to live life. Emphasizing the diversity of consistent and possible answers to the meaning and goals of life.

1984 (nonfiction) - Classic. Newspeak, Ministry of Truth, Doublethink, Thoughtcrime, Facecrime, Unperson, the list just keeps on going. Chilling world-building and the realization that weaker equivalents of everything exist.

In Defense of Food by Pollan (nonfiction/food) - Eat food. Not too much. Mostly plants. The book that first taught me to avoid the entire center of every grocery store and only shop on the outer ring. The realization that the food industry is out of control and the things they do with your food, what they put into it, what they are allowed to do, and how they are allowed to market it to you is quite a lot worse than I thought.

The Accidental Superpower by Zeihan (nonfiction/geopolitcs) - I've found Zeihan to be a bit of a mixed bag over time but I still remember his books (esp this one) to be elucidating on geopolitics.

Countdown to Zero Day (nonfiction/cyberwarfare) - Goes into detail on Stuxnet, imo very important and highly elucidating reading on cybersecurity, the future of warfare, and AGI.

A Fire Upon the Deep (scifi) - Chapter one only, incredible portrayal of what superintelligence will be like that has stayed with me since.

Guns Germs and Steel (nonfiction/history) - I'd probably recommend a summary of this book more than the book itself. I remember it being very dry, but it was very interesting because it is a comprehensive analysis of the resources grid (food, animals, freshwater, climate, ...) in our real-world game of Civilization, and the implications there of.

Flowers of Algernon (scifi) - Just a totally crushing masterpiece on intelligence.

Atlas Shrugged (scifi) - No one finishes this I think but the first few chapters and its worldbuilding are enough and, once seen in an exaggerated form in fiction, elements of it cannot be fully unseen in reality.

An Immense World (nonfiction/bio, by Yong, among others of his) - Nice book on so many different sensors used by various animals, you repeatedly realize human senses are super inadequate and that we only measure such a tiny sliver of reality.

The Master Switch (nonfiction/tech history, by Wu) - history of information technologies telegraph, telephony, radio, television, film, cable television, internet and the pattern of "The Cycle", where each medium starts decentralized, open and idealistic and then progresses towards centralization, control and oligopoly, for the very similar reasons, by very similar means, and usually at the expense of diversity, innovation and technological progress. Quite a few connections to draw on for LLMs, which are after all an information technology too.

(I take recommendations for more that are likely to make this list!)