Nothing.

Nothing!

Nothing.

Get the home furnished and see how you feel about the columns then. I tend to think that they are fine as they are. If you don't care for them when the room is full of furniture, then a live plant (careful with the floors) or perhaps an almost life-size piece of sculpture with a true Grecian look to it might be interesting, depending on your furniture style.

I agree with @decoenthusiaste, it will look fine once all the furnishings are in place, including window treatments, accessories, wall decor.