Are you planning curtains/other WTs, or any furniture there? If not, you could do a few things:

Beef up the trim:

Add a cornice:

If none of the above, I’d leave it bare (it’s a nice calm space), or add decorative and unique plates (or baskets). Look on Ebay, Etsy, local places, etc. Collect some that you love.

Plants might look nice, too, in front of the window.

I have a similar bay window in my dining room. I am going to do what Jinx shows in the third picture - a box valance. This is what happens when they place windows in a room with a 9' ceiling that belong in a room with an 8' ceiling. There is too much blank space between the top of the window and the ceiling. The valance solves the problem. Smith & Noble make them in a variety of fabrics.

Thanks for all the comments and suggestions. Our style is more modern/eclectic than any of those examples unfortunately. Any suggestions that are a little more subtle? I don't want to "beef up" the design too much. It's not really a focal point of the room

Then I’d leave it bare.

I agree that the space is begging to be filled not only with something above the windows but also below. A simple, curved rod mounted high can subtly break up the space and light drapery panels can frame a piece of furniture like a console table with lamps or plants or a small seating space.