I'm currently on Neal Stephenson's Anathem, and The World Without Us, by Alan Weisman. The latter is a non-fiction book in which he examines the question of what would happen to all the stuff that civilization has made and built if the entire human race were to suddenly disappear. It's not a great book, but it's fairly interesting. He looks at a lot of different facets of the question; from what plants and animals would thrive, to what happens to all the plastic that we make. Should be a reference book for any writer who's working on something post-apocalyptic. :-)
I generally have one fiction and one non-fiction going at any given time. If I finish World, I have Lion in the White House waiting, which is a biography of Theodore Roosevelt. It's highly unlikely I'll finish Stephenson before Christmas, but the next fiction that comes off my shelf might be Axis by Robert Charles Wilson. (I really liked Spin.)
Merry Christmas, or whatever holidays you may be celebrating.
"It's only Neutron. We call him that because he's so positive." --from This Island Earth