We finished the stairway down to the basement and half the basement. We're really happy with it. It's definitely going to help sell the house and I get to enjoy it until we go to sell. Best part, it only cost $15k including material and labor. In our case we're looking to add sell-ability not add $ to the sale price. A bonus room is a major selling point. You definitely want a basement sump pump system. You also want to use DriCore flooring or something similar.