Of the two, as is, I'd go for the Family Room If its not used on a regular bases. you could still keep the ex bedroom for guest or use it for one giant fabric storage closet, shelves on all the walls and a couple down the middle LOL But if you felt lonley in the spair bedroom on the main floor and moved into the breakfast room your are going to feel lonley in the basement to. Remember it is also out of the main living area. Could you talk DH into moving his favorite chair and TV into the new sewing room to keep you company?