I read all kinds of books (one of my friends jokes that I will read anything that holds still long enough), but sci fi/fantasy is my favorite. I also love books on anthropology and archaeology and other sciences.
I adored this book. It really answers the "what if" questions you always seem to get when taking a history class. I love how it shows just how scary it would be if you had to fear saying something in your sleep and having your kids report you.