Zanni

Seconding Dune, which is a classic for a reason

I'd suggest Cryptonomicon over Diamond Age.

Orson Scott Card's Ender's Game is fantastic

over Diamond Age

The Moon is a Harsh Mistress is a better place to start with Heinlein

Seconding Dune, which is a classic for a reason, and Stranger in a Strange Land

The War of Art by Steven Pressfield. This is the book I've recommended more than any other

Ted Chiang's Stories of Your Life and Others is the best, single-author collection of short stories I've ever read.

his follow-up collection Exhalation

my favorite science fiction novel of all time

Redshirts, a Star Trek parody, rivals Galaxy Quest

Many more in this series, if you get into it.