The Uplift War, David Brin. Less sure I originally read this now, though I do recall reading some of his stuff in the Uplift universe. A good read though.
Neuromancer, William Gibson. Excellent first book, and the progenitor of an entire genre.
Downbelow Station, C. J. Cherryh. Nice galactic civil war tale, though the noble, wise, pacifist alien race is a touch cliched.
The Snow Queen, Joan D. Vinge. Better than the cover.
The Fountains of Paradise, Arthur C. Clarke. Man versus Buddhists over a bridge to the stars. Lightweight, but could be prophetic (as Clarke's satellites were before).
Rendezvous with Rama, Arthur C. Clarke. Alien vessel passes through the solar system, humans don't really find out much about it.
The Gods Themselves, Isaac Asimov. Two universes discover they can get free energy - but it turns out there is a cost.
To Your Scattered Bodies Go, Philip José Farmer. Weird. Richard Burton (not the actor) wakes up after he died to find himself on a new world where he manages to boff Alice from Alice in Wonderland and fight Hermann Goering.
The Left Hand of Darkness, Ursula K. Le Guin. Le Guin explores gender politics on the planet Winter, where the inhabitants have been genetically adjusted to wander between the sexes.
Next, Michael Crichton. Crichton has a lot of points he wants to make about genetics. However, he decides to hide them under a plethora of half-conceived plots, characters so broadly drawn they don't deserve the term stereotypes and ugly attacks on people who've criticised him in the past.
The Afghan, Frederick Forsyth. Techno-thriller about how awesome the British and US are at tracking and thwarting terrorists, in large type.
The Terminal Man, Michael Crichton. Better focused work from Crichy. A man who suffers from sudden rages has a device implanted that triggers pleasure sensations when it spots a rage attack - however, he learns to control it without suppressing his rage.
Northern Lights, Philip Pullman. What Rowling wished she could write, a children's book around adult ideas.
Under the Banner of Heaven, John Krakauer. Krakauer investigates what led two brothers to murder a woman and her infant daughter, and if it's related to their Mormon upbringing.
The Prefect, Alastair Reynolds. Another of Reynold's Revelation Space novels, this one exploring an earlier time than most of the others prior to the Melding Plague. Decently awesome.