SFGate

gkemp what is your ceiling like? can you take this angle a little higher up to show the ceiling line? how high is the ceiling?

chautime Here's a picture of the ceiling.

chautime I am estimating the ceilings to be about 15 to 18 feet high.

harpah Hi I think These would look good in all 4 windows.

Emiliana Patriotou Hi, we are a textile consultant and window coverings firm and have done many projects so far with this type of windows. Ideally you don't cover the walls with a curtain but here are two approaches regarding your living room.
a. Hung one curtain in a sheer fluid material (try Georgette) with a lot of pleating starting from the ceiling of the central window and ending right down to the floor. This curtain will be as wide as you wall, which is wider than the window itself. (please see image attached for idea). The other two lower windows on either side can have roman shades in the same color as your sheer curtain but in a more sturdy material, lined etc.
B. The second option is two have roman shades for all windows (4 Roman shades) in a material that is rather eye catching so that you divert your attention from the bare wall and dress up your wall this way. (see pic for shades in multi colored tweed shades)

kdkaier I would suggest a floor to ceiling lightweight fabric to add a visually dynamic focal point. Using a heavy weight fabric creates a bulky appearance, while a medium to lightweight fabric creates an effortless flowy design.

Diamondflame I would go with Emiliana's option A. And please do reconsider the fan+ lamps combo and go with floor + table lamps option.

DIAspoton have you considered art? 2 very large originals might be cost prohibitive. however, having two cool black and white photos blown up and stretched over 2" canvas frames and hung isn't bad. google companies for prices. add white painted moulding around lower windows.

so many angles with the furniture. this wonderful spaces lends itself to two tufted solid color crescent sofas with a round coffee table to mimic the arc of the room.

Patricia Pelgrims The top window needs no dressing up with fabrics, curtains, blinds. What you could do (at a cost) is have a stain glass window in there.
No need for extra artwork alongside it then. Let that window speak for itself.
The other windows can be dressed in anything you want, provided it is neutral.