This is a perfect combo of my two favorite ideas for that space under the stairs leading to the basement. A reading nook AND book storage and shelves . assuming that there is enough space for this there.
Staircase storage - Simple version for under stairs storage. This would totally work if we gutted the basement as it is now. (Plus, no more dark crawling under the stairs to get at my christmas decorations!
Look for dead space under stairs and in deep walls. There is often room under a staircase for a small closet, powder room, or even built-in shelves for cataloging books, files and other knickknacks that create clutter.