This year I got into a history binge after I finally got around to reading Caro's Master of the Senate this January. It was so good I'm already ready to read it again.
I used to be scared of tackling big books because I don't feel strongly committed. But with these I did audiobooks for the first time, while cleaning and driving and cooking and it has made reading big books merely a matter of time.
Other than Caro's books this year, I really liked the three-volume Churchill biography by William Manchester. And the first two volumes of the Teddy Roosevelt biography by Edmund Morris.