Hi Lindsay, The longer sideboard would look nice if you're not planning on adding any furniture flanking its sides in the future; maybe add tall plants on both sides too. However, if you're looking into adding cabinets in the future, I feel the shorter sideboard would be better so you have more space for future furniture, maybe two identical cabinets that would take up the whole wall on each side, and since the window is the same length as the window, it would help it look more put-together.