Appliance selection is relatively limited - Corripio in Ver?n, Ferreteria Americana in B?varo past Friusa. Might be worth taking a trip to the capital for a broader selection, especially if you're after high-end stuff.
Basic household items in the place by the bakery in Plaza Ta?no (Coco Loco crossing), and plenty of designer style home accessory places like Casa Cana, Home Expressions, and several at Plaza Bolera in Punta Cana.
Large furniture stores include Ilumel on the way to the airport which caters for a range of tastes and Unicane (Av. Estados Unidos past the Friusa crossing) but there are several others dotted around the area.