A bookcase would seem out of place IMO and not really fit with the style of home.

This is the living room next to entry way-the sconces have been romoved. Doubt this helps much I can take more pics this weekend-

What about a bench and a large piece of art? Something along these lines:

Custom Atlanta Home · More Info

I like bookcases, particularly when they're full of interesting and/or well-loved and read books or even a few interesting object d'art scattered among the books. A really beautiful antique piece would compliment rather than detract from the woodwork.

I would prefer a low and open piece on the bottom with large art above. Could be an etagere or a bench as others have mentioned. The problem for me with a bookcase is that the sides will intrude too much into the sight lines, even if you have one custom made on the shallow side.

I haven't, but I wow! I don't think you could make a mistake in that beautiful home...

I would say to go in the direction of "more is more"....

And yes, I would go with a dark wood...