Just finished reading The World Without Us by Alan Weisman.
THe premise of the book is to answer the question of what were to happen if humanity were to suddenly disappear from the earth and leave the rest of its living things and structures in the same state they are in currently (if we were all to be Raptured for example).
Partly apocalyptic, partly hopeful. It is quite interesting. I decided to order it after seeing the author interviewed on The Daily Show in late August.