I agree with most or all of those posted. Asimov, Heinlein, Herbert, Clark, Niven and Pournelle (collaboratively), Poul Anderson, and so on.
Missing is David Brin who hasn’t yet written a bad book.
The Uplift series is great, The Practice Effect is unique and The Postman is a modern-day classic.
I enjoyed Heart of the Comet, written by Brin and Gregory Benford.