panels on rings on a rod mounted below the semi circle, and wide enough for the drapes to fully move off the window to the sides. pottery barn has some nice ring styles that arent clip ones, which might make your drapes dangle lower than you'd like.

if you have no heating vents along there you can have them any length you like. if there are heating vents having them puddle or a 2 inch break does quite a bit to keep them from blowing around.

for width, you need double the window width. to figure out stack space needed, the thicker the drape the wider the stack needed.

if you want privacy all day long, do a double layer with sheers staying still and heavier panels moving over at night.

if your windows are deep enough you could do inside mount fabric shades.

Any ideas on what colors, and styles I should be looking for?

A few pictures with better angle.

We put wood shutters in our front facing dining room. We are able to let in light while maintaining some privacy. They can make a shutter thing for the arch too, but if you do not have privacy issues through that part of the window, it is not necessary.

Should I go with a print on the drapes, or stay solid? This other room opens to it and has same style window. Should I keep the same?

This is pretty and could go in both

rooms

What if I used something with a print like this one. I'd like a way to bring some color into the living room.
http://www.overstock.com/#/8232606/product.html

I like these a lot but not sure if they could be used in both rooms.

Forgot to link : http://www.overstock.com/#/8285923/product.html

Wrong link, I'm not looking for the drapes in blue, but rather an orange.

Table and chairs are in

Have you considered a shutter?