Neuromancer: Damn, what can you say? This ground breaking novel started that whole damn thing. Even more amazing is that Gibson wrote this novel, which had computer geeks orgasming left, right, and center, was written on a typewriter. Gibson was totally computer illiterate at the time.
There was a graphic novel version......eh...it was ok. Nothing to write home about, IMNSHO.
Count Zero was a damn good followup.
It has these great lines that just stick to you, like: "They bought eyes and genitals on the open market. The eyes were green."
He took an interesting stab at Steampunk with Bruce Stirling with The Difference Engine. An interesting work, worth the read, but not my favorite from a well constructed novel viewpoint. A very interesting alternate history book though.