drapes would just hang funny when you look up the stairs.
Get the window tinted.
or get a remote blind that can open from the top or bottom, in white.
The simple architecture makes this awesome, fluffing with with drapes...eh.

No drapes....window film.

A honeycomb shade that filters light would be nice, or a roman shade in a white/black/grey patterned fabric would look good too. Window film is also a good idea if you never like to look out of the window.