All of the books below have received some sort of review on my GoodReads site so I'll confine myself to a few brief notes. Note, too, that this certainly doesn't exhaust the list of stuff I read between June and December 2008, this is the cream of the crop:
The Fiction Roll -
The January Dancer, Michael Flynn. Probably the best new SF I've read all year.
The Nature of Monsters and The Great Stink, Clare Clark.
Toll the Hounds, Steven Erikson. Book 8 in The Malazan Book of the Fallen.
Dark Sleeper and The House in the High Wood, Jeffrey Barlough. A mixture of Dickens and Lovecraft; the former predominates in Sleeper, the latter in House (whose ending is one of the most profoundly creepy I've ever read).
The Coroner's Lunch, Colin Cotterill. A mystery series that follows the adventures of a Laotian coroner under the Communist regime. I can also recommend the second in the series, 33 Teeth.
Un Lun Dun, China Mieville's stab at young-adult fiction. Very good.
The Nonfiction Roll -
The Horse, the Wheel & Language, David Anthony
Who's Been Sleeping in Your Head?, Brett Kahr. A look at "normal" people's sexual fantasies.
The Geese of Beaver Bog, Bernd Henrich. One of the best nature books I've ever read.
The Singing Neanderthals (Steve Mithen) and Inside the Neolithic Mind (David Lewis-Williams). I put these two together because they're complementary texts in my mind: The first looks at the origins of music and language; the second looks at the origins of spirituality and religion in modern homo sapiens.
The Ruin of the Roman Empire, James O'Donnell
How Fiction Works, James Wood
Barbarian Tides, Walter Goffart. A dense book, not for the faint hearted but well worth the effort.
The Suspicions of Mister Whicher, Kate Summerscale
Young Stalin, Simon Montefiore. Stalin's life before he became Stalin.