I loved Gibson's books and he re-defined cyberpunk for me. However prior to that there were an number of Philip K. Dick novels (Ubik for one) and even some John Brunner (Shockwave Rider) That paved the way.
I for one would not consider Do Androids Dream of Electric Sheep (Blade Runner) as Cyberpunk. Sure it has the Noir set in the movie--which I honestly did not manage to feel as impressed or oppressive in the novel. But it lacks the inner space-iness that you get in classic Cyberpunk. There are plenty other PKD novels that come closer.
John Shirley has some good stuff--however I started reading him through a recommend of
I didn't really feel that the cyber elements were that prevailant throughout ASCYS however they are much stronger than what you might see in PKD's D A Do E S (once again it is sometimes difficult to get that noir feel--ASCYS was much more war-torn and dystopic. I think the noir shows up as something that civilization settles into after all the war and some dystopic period to become a norm that is accepted by those who are trapped in its center. (And that might color the way I read these.)
Oddly I thing CyberPunk shouldn't be limited with words like dystopic and Noir, because I think that it could all take place in places of the world that try to shield themselves from those elements and still succeed as a CyberPunk. Those two tropes just happen in this moment to be ones that excite the reader imagination.
There's a good chance that that will change.
Rudy Rucker has some good stuff--and it is less noir because he has some of the Singularity stuff going.
Charles Stross has a good number though his tend to be light on the cyber-much like Shirley's ASCYS.
You could almost enter Stieg Larsson's Girl' books in the cyberpunk when considering some of the mainstream work that includes such thinly peripheral development in the cyber arena.
There also seems some bits of parallel to Noir and the darker deeper political thrillers.