I'd want to see ore of the room and furnishings with good lighting in order to make an informed suggestion.

I'd do roman shades.

About faux stain glass film or something like this one

http://apex-window-film-store.com/store/home.php?cat=363

I would think that soft roman blinds in a cream color maybe with a coffee coloured stripe if you don´t want a plain fabric would dress the window without taking away too much light, they could be installed in the space above the window and when you need as much light as possible you could pull them up to the top of the window.

I would advise against any curtain panels-would love to see the rest of the room though. You'll cover too much glass--and you don't want it any darker. Is that your screen I seen inside the frame? If not, I would look at a Hunter Douglas Silhouette. Will lets lots of light still come in.

very good