How can I decorate this wasted space above the kitchen & staircase?

I would paint that wall a really rich accent color. Then I would use a lighter version of the color in the kitchen. This should draw the eye up and the kitchen will appear less prominent

Becky...I love the simplicity of what you have done! I see no need for anything else but that's just my opinion. I'm sure you will get some other ideas however from your friends at Hometalk!

Becky: i agree with tinyshoes -- sometimes less is more!

Crown molding in white, boxing the triangle in.

Thrift store & marketplace shopping to find items that suit you. You could also paint in a contrasting color.

Amass a collection of most loved pictures, prints, painting - frame alike and hang.. Look at thrift shops , garage sales.

I Don't think it is wasted space. Love that !The only thing that I would do is to add a trim to openings in the light color

I agree with the crown moulding idea. It would give that triangle a sophisticated, polished look.

I don't actually see why you would want people looking up there. You should be trying to draw attention downward so I say leave it blank.

I agree with Laura Cooper

Looks good to me. Maybe add crown molding to finish it off. 👍

Becky, did you make a decision?