I just recently finished reading the second of two history books that I received over Christmas. The first, American Lion, was about Andrew Jackson. The second, Team of Rivals, described Lincoln and his cabinet. Both were told through extensive use of primary sources, mainly personal correspondence. Both were long, but e the end very good, and this comes from someone who doesn't read much history.
Lincoln is especially fun to read about since, as you may have noticed, he is sort of a super hero/mythological character in American society. It's hard to know how much of this praise is warranted. Team of Rivals, gave me a great impression of Lincoln, but what seemed to be an honest one. He was definitely a politician, but an excellent one in that he succeeded uniting very different groups within the Republican party. He was the kind of guy that everyone liked once they met, but was often made fun of. It was especially funny to hear him referred to as the "prarrie lawyer," since at the time being from Illinois not exactly a mark a sophistication.
Okay, in short I would highly recommend both books if you have a fair amount of time on your hands!