For me it was The Walking Dead
series. The characters are burned into my memory with some of the all-time greats.
It wasn't my most prodcutive year, only 15 books or series read and 3 other books which I did not finish for various reasons. Discovered some interesting new authors anyways. Christopher Moore, Dan Simmons, Alfred Bester, Joe Halderman, Margaret Atwood, Larry Niven. On to 2012.