Have you read any of Sarah Vowell's books? She sets a very dry, often witty, tone in her books, but she's a solid historian and a great storyteller. I especially liked Assassination Vacation, which looks at three presidential assassinations and the effects they had on the country.

I also recommend When Everything Changed: The Amazing Journey of American Women from 1960 to the Present by Gail Collins. I particularly enjoyed reading the chapters on the experiences of African-American women in both the civil rights and the women's movement.