Spook Country, William Gibson
This man does not need to write about the future to be visionary (though we already knew that from The Difference Engine).
Gibson is not an SF writer; he is a writer. And what we love about his writing is: its precise brevity, its heart-racing mechanics and its literary breadth.
Funny thing is I usually forget most of them. Love the martial-art style action here that he pulls off as if you were watching a movie.
Love the language, both narrative and dialogue, purified to its essence.
And one thing that struck me that I've observed before but not thought about: if you are reading any piece of any other fiction or non-fiction in parallel to reading Gibson where you come across some obsure fact, it's likely that you will find at least some of those facts in Gibson. Case in point: volapuk. Why did the first time I've heard of this thing immediately become the second time I've heard of this thing? Because I was also reading Gibson, and he's heard of everything.