Dune has held up pretty well, though that's probably because it takes place in a future in which computers have been outlawed, so you don't have the giant mainframes common in SF up through the '70s.

I also gotta give a shout out to Bester's Stars My Destination, which is dated as hell but full of so much insane batshit action set pieces that it feels like a modern day action movie.

And I only just read it last year, but damn, Pohl and Korbluth's Space Merchants feels weirdly prescient. (Just avoid the recent revision by Pohl which updates the book with references to modern companies like Google and Microsoft.)