So, in no particular order:
Behind the Beautiful Forevers by Katherine Boo (Truth in Journalism): a non-fiction book with a story more powerful than a novel.
Train Dreams by Denis Johnson (Worth a Second Look): How can the spare story of a simple life leave such a lasting impression? Johnson's beautiful prose makes that happen.
The Custom of the Country by Edith Wharton (A Master at Work): One of America's most influential novelists reminds me why her reputation is so richly deserved.
What Happened to Sophie Wilder by Christopher Beha (A Question of Faith): I don't know why, but this one just really stayed with me. Maybe because Beha asks hard questions.
Billy Lynn's Long Halftime Walk by Ben Fountain (A Day in the Life): Maybe it's because I read this one so recently, but I'm still marveling at how a short book can be so American, so funny, so vivid, so sad,
And yes, I do have runners-up:
Arcadia by Lauren Groff (Commune Life): Revisiting commune life without romanticizing it.
There but for the by Ali Smith (Words, Words, Words): The most unusual premise of the year.
Salvage the Bones by Jessamyn West (Weathering the Storm): A young female protagonist who isn't plucky or adorable, just honest.
Skios by Michael Frayn (Greek Delight): Strictly for the laughs.
Gone Girl by Gillian Flynn (Summer Reading): My addictive guilty pleasure this year.