1. The Battle of Pea Ridge: The Civil War Fight for the Ozarks by James R. Knight (The History Pr, 2012).
Knight has published three Civil War books with this press. I don't know anything about his Donelson study, but his Franklin overview was good. With a great deal of attention paid to both unit positions and terrain (even elevation lines), the original Pea Ridge battle maps that accompany this one are nice.
2. Unholy Sabbath: The Battle of South Mountain in History and Memory, September 14, 1862 by Brian Jordan (Savas Beatie, 2012).
Previous histories of the fighting at Fox's, Turner's, and Crampton's Gaps by Priest, Hoptak, and Reese have their strengths, but no single work puts it all together in the manner and level of detail that this one appears to have done.
On another note, from the same publisher, there's a nice excerpt available here from their upcoming collection of Petersburg battle articles.