My all time favorite series is the "Sprawl Trilogy" written by William Gibson. My favorite book is "Neuromancer", the first of the trilogy. It is truly one of the best Sci-Fi Cyberpunk books ever written and is basically the template for newer books such as "Snow Crash" by Neal Stephenson, which is awesome in it's own right.
Neuromancer's characters a deep and memorable, the plot is think and juicy, and the writing itself is pure poetry. I highly recommend Neuromancer and the two books that follow not to mention all of William Gibson's writing.
http://en.wikipedia.org/wiki/Neuromancer