If you start to include books the remit becomes utterly massive. To the above list I would add:
Wells, Verne, Vonnegut, Orwell, Banks, Brin and my four current favourites (all Brits) Douglas Adams, China Mieville, P.F. Hamilton and Alastair Reynolds. Add those to all the others mentioned in this thread and you've got a ridiculous number of possibles.
I know Mieville isn't really S.F. but I really wanted to mention him.
Not sure Hari Seldon ever knew what the clinically insane were going to do so I'm fine.
Edit: To Gunslinger, the next two in the Revelation Space trilogy (Redemption Ark and Absolution Gap), are quite a lot better if you don't mind most of what he writes being in essence an extended chase sequence. Chasm City is not part of the series, only in the same "universe", although it does flesh it out a bit (talking about the melding plague and such.)