People have different definitions of what makes a book great. I look for books that teach me something, inspire or inform my work, crystallize an idea or are just a great read. Of the books I've reviewed this year, here's the list of the ones that did all of these to at least some degree:
The Big Switch, Nicholas Carr
When Markets Collide, Mohamed El-Erian
Who's Your City? , Richard Florida
Billions of Entrepreneurs, Tarun Khanna
The Back of the Napkin, Dan Roam
One Hen, Katie Smith Milway
Creating a World without Poverty, Muhammad Yunus Post your candidates in comments, and I'll work up the voting list.