USA Today's top 100 bestsellers included exactly one Civil War title. Coming in at 92, it's the novel Cold Mountain. That's it.
Let's look at this title using today's sales data from Ingram, B&N and Amazon.
The Cold Mountain's paperback edition, offered by trade giant Random House, sold about 60,600 copies so far this year (10,096, Ingram); last year it did around 92,800 (15,458, Ingram). The hardback, brought out by The Atlantic Monthly Press, sold about 7,700 so far this year (1,282, Ingram) and some 14,500 last year (2,407, Ingram).
I will go out on a limb and say that the movie and DVD releases must have helped book sales somewhat, but they were not long-lived enough, not "hot" enough to generate ongoing bookbuying at this level.
Oddly enough, Barnes & Noble gives the paperback a sales rank of 8,092 and Amazon ranks it at 1,954.
This is what the bottom of the top 100 looks like in terms of commercial success. Compare and contrast with our nonfiction Civil War book sales thread.