Non-Fiction

McPherson's Battle Cry of Freedom was on my reading list in grad school, and was one of the more enjoyable reads. Great coverage for a one volume work.

Faust's This Republic of Suffering: Death and the American Civil War I found fascinating because it explained the war's significance to the rise of spiritualism in post-Civil War America.

A few I would add to the list:

Gordon Rhea's trilogy on Grant's 1864 Overland Campaign:
The Battle of the Wilderness May 5–6, 1864.
The Battles for Spotsylvania Court House and the Road to Yellow Tavern, May 7-12, 1864 and
Cold Harbor: Grant and Lee, May 26-June 3, 1864. I didn't find the book on Cold Harbor as compelling as the others, but it may simply have been the nature of what he had to try and make sense of in that volume; or, I could simply be dense. My wife casts one vote for "dense."

Gregory A. Coco's A Strange and Blighted Land -- Gettysburg: The Aftermath of a Battle. addreses something not often covered in other studies...what it was like for the civilians, etc., who had to deal with the battlefield both armies left behind.

Noah Andre Trudeau's Gettysburg: A Testing of Courage because of the manner in which he broke the battle down on a timeline.

and

William Freehling's The South Vs. The South: How Anti-Confederate Southerners Shaped the Course of the Civil War which was interesting because it educated me on the fact that "the South" was never a monolith when it came to slavery, or the Civil War.

Man...you start thinking about it, and the lists could go on for days.