Haha, I'm always simultaneously surprised by how many people have read War For the Oaks and how many people have never even heard of it. My head can't seem to quite grasp whether it should be considered a popular book or not...
Fantasy: (Arg, too many to count or remember) The Way of Kings by Brandon Sanderson, Parsifal's Page (book four of a series) by Gerald Morris, the Erec Rex series by Kaza Kingsley. the Bartimaeus trilogy +1 prequel by Jonathan Stroud, Ysabel by Guy Gavriel Kay, Finnikin of the Rock by Melina Marchetta
Mystery: The King of Lies by John Hart
Action: Ice Station by Matthew Reilly. The Altar of Eden by James Rollins
Romance: On Mystic Lake by Kristin Hannah, All Night Long by Jayne Ann Krentz
Nonfiction: Little Princes by Conor Grennan, The Devil in the White City by Erik Larson