Because the bay is an extension of the floor itself (as opposed to ending at windowsill level), I'd go with three short rods that follow the bay. This will keep the floor space available for any additional piece of furniture you might want or need. A deep color like navy blue would have weight that would go well with the large-scale and rich leather of the sofas. To avoid blocking the view, consider just swags across the top, or perhaps swags with jabots (you can find images of these online, and they are easy to make). Good luck making this room a place you enjoy to the max!

Here is our suggestion for the window dressing: