Window decoration and stained glass windows

Fantastic; a bay window with stained glass. But what window covering can you use in these windows, without destroying the overall character?  Stained glass windows are works of art in their own right. They often tell a story or add extra colour to a window feature. Sun shining through stained glass windows results in an eye-catching, colourful effect. But even without incidental light, these windows are more than worth looking through. It is a real shame to conceal such beautiful windows...