I have always counted Orson Scott Card's 'Ender' series as some of my favorite books. Ender's Game, Ender's Shadow, and several others. If you have not read them, go get them, if you like really good sci-fi.
His other writing is just as good - this article explains why he's voting the way he is. Go read it here. It is quite long, so take your attention span with you.