What Do You With Internal Windows?

We have a window in our living room that leads to the sun room.  I'm almost certain that our sun room was an addition and the window was just left as is.  We've always worked around it and have dreamed of maybe one day replacing the window with a built-in bookcase.  This would require brick work, etc.  Lately I've been curious and so I began collecting pictures of how others work around their internal windows.  I'm glad I did because these images are all really nice.

I found it interesting that each window was bare - as in no window treatments.  Of course mine has a bamboo shade and curtains (figures).  It also seems like the windows in the images are ignored which might be the best scenario.  In most cases they simply allow a glimpse into the next room and possibly add light to the space.

Now I'm beginning to feel like I'm over thinking it.  What would you do with an internal window? Would you ignore it or treat it like any other window?

images:  1, 2, 3, 4, 5, 6