Instead of curtains I would change the rugs to have more white to carry the white of the window walls into the centers of the room. If you don't want a light rug, then at least have throws or pillows that have a lot of white in them.

I think your Christmas decor was very pretty!

I do like the color a window treatment can bring to a room. I also like the cozy feeling in the evening when the shades are pulled down.

This is a possibility:

What a beautiful space! I wouldn't do curtains, just possibly woven woods or a silhouette-type shade, inside-mount if you are able.

Wow...those windows don't need much of anything! If you decide otherwise, I'd go with an inside-mount shade similar to jhmarie's example. Keep them simple...let the windows be the focus.

Only if privacy is an issue! There are always now you see them, now you don't options like shades!

Thanks everyone for the comments/suggestions. For the time being, I'm going to leave things as they are. I think I may need to work on convincing Mr. CeeBee to let me paint in here, though. I'm afraid adding white accessories - let alone a rug! - is not an option (we have a dog & kid and really LIVE in our home, with all the attendant dirt/messiness!), so perhaps I should consider introducing color on the walls. I am horrible at choosing colors, though - things never seem to coordinate like I want them to. Maybe I will post a separate dilemma for that. :-)

Just one more suggestion: I would install stationary curtain panels on either side of each window just to add