The Border Town by Shen Congwen (1934) — Not set in Changsha but in the Miao borderlands of western Hunan; this novella is the essential introduction to the landscape and people of the province. Shen's prose has a quality of suspended melancholy that captures something true about this part of China.
Wild Swans by Jung Chang (1991) — A family memoir spanning three generations of women in twentieth-century China, with sections set in Hunan. Chang's grandmother was from Yixian, and the book's account of the Cultural Revolution in Hunan is one of the clearest first-person records in English of that period.
Mao: The Unknown Story by Jung Chang and Jon Halliday (2005) — A comprehensive and deliberately hostile biography of Mao that includes detailed coverage of his Changsha years. Whatever you think of its argument, the Changsha sections are well researched and provide a counterweight to the devotional atmosphere of the official sites.
The Travels of Lao Can by Liu E (1907) — A late Qing novel about a wandering healer that gives a vivid picture of provincial China in the years before the Republic. Not specifically Hunanese but essential context for understanding the world in which the twentieth-century revolutionary movements emerged.