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.
Natural light is a major mood booster, not to mention a major selling point in any home. The warm kiss of sunlight indoors will make your space feel bigger, cozier, and way more put together than any dimly lit fluorescent light bulb ever could.