I like things to feel real.
I like villains who you hate but wish that you could have been there earlier to keep them from becoming a villain. The author Alfred Ollivant introduced me to that in Bob, Son of Battle. I was pretty young when I read that novel, and most of the stories intended for my age had a simply evil villain that you never understood or tried to understand. How different were the villains of Bob, Son of Battle! You understood why everyone hated them, and yet a small part of your heart cried for the villain.
I like a good mix of action, philosophy, dialogue, and description.
I like a writer that will make me laugh. I don't mean a comedy novel but something that will, somewhere in its pages, pull a laugh out of me. Sometimes it is a funny scene, sometimes it is a bit of wit, and sometimes it is an unexpected comparison.
I like a writer that makes me feel clever. When a writer trusts my intellect to understand him or to understand a reference he makes, that makes me feel clever...unless, of course, I don't understand him...in which case I might dismiss him as stupid for not being able to explain himself better. Readers can be so unmerciful at times.
...which leads me to my next point: I like a story that is easy to read. Some writers have a flow with their words that is nearly profound in its simplicity. A book does not have to be difficult in order to be great.
I like a description that is so unique and yet vivid that I can instantly see the picture and feel its heartbeat.
I like a story that will inspire me, that will make me think, and that will thrust me toward action. I like stories with good morals and good points to make.
I like an author who can capture my deepest feelings and put them into words with such an eloquence that matches my inmost thoughts. It's not easy to convert an inmost thought into eloquent words, but there is a place in my core that sings -- almost like a violin string vibrating under a bow -- when it meets its essence in print.