I distinctly remember reading Asimov’s Foundation series over 40 years ago. Made a huge impression.
Recently tried to read it again. Almost unreadable.
Hopefully some of his enormous body of work holds up better.
Some authors are have held up much better over time. I personally think Heinlein is one of these, although I read a recent online panel of SF critics who came to mixed conclusions.
http://www.locusmag.com/Roundtable/2011/10/roundtable-heinlein-juveniles-then-and-now/
As one of them put it:
"Would they be willing to keep reading a book, though, where the “current-day” stuff is so different from the world they live in themselves, where there are no cellphones or personal computers or Facebook, where kids work as “soda jerks,” something that most of them have never even heard of? Will the fact that most of these books start out in a “present-day” that’s clearly the 1950s rather than the world that kids today are familiar with make the present-day part just too dated and alien from their own experience for them to be able to get through it to the Sense of Wonder stuff that eventually follows?"