Let me mention a few books I've read this year that I want to recommend whole-heartedly.
Cory Doctorow's Little Brother (9780765319852) from April 2008. Yes, it's a YA title, but as far as I can tell that just means that protagonist is an adolescent, not that the story is dumbed down. Themes include hacking, cryptography, civil liberty, terrorism, data mining, linux, sex, and civil disobedience. Doctorow's best book so far.
Neal Stephenson's Anathem (9780061474095), to be released 2008-09-09. I can't stress the awesomeness of this book enough. Themes include Platonic forms, directed acyclic graphs, kung fu, Gödel metrics, monasticism, space travel, long-term timekeeping, a cappella music, conscienceless, the chronology protection conjecture, and the true nature of quantum mechanics. Just reading that list might have given way half the story. The book is a masterpiece.
Charles Stross's Saturn's Children (9780441015948) from July. Not his best book, as far as plot go, but worth reading if you care about the extinction of humanity, robots, robot sex, and the slowness and uncomfortableness of space travel.