The best room in the house (for your plants) is the bath. House plants perform well with natural light and shower mist; as an added bonus, they also purify the air. Since you probably don't have an outdoor bathtub, they'll bring a touch of green indoors.
Above: House Balalla Kavanagh in Australia by Tribe Studio Architects.
Above: This courtyard of schefflera plants and light in the bath from Suppose Design Office in Japan is second only to an outdoor bathtub.
Above: Mother-in-law tongues from Houseplants as Camouflage.
(N.B.: For the real outdoor bathtub experience, see "5 Favorites: Outdoor Bathtubs.")