I'm biased against Asimov --- which I'm sure is a great suggestion and thank you --- because I got it in grade school and it put me to sleep. Was I crazy, or is stuff like Snow Crash just a whole lot more fun to read?
Asimov's short stuff is much better than his novels. It's not SF, but you might try his Black Widower stories, I think there are 3 or 4 collections of them, they're short brain-teaser stories.
While I agree with you to an extent, Neal Stephenson also gets panned for writing long-winded stuff, like Anathem or the Baroque Trilogy. I just view it as dense brain-food, but some people get turned off.
