Aloe

Aloe vera is well-known for it's soothing medicinal properties and also makes an architectural and low maintenance houseplant. The leaves are fleshy and retain water, so you don't need to water very often - once every two weeks is about right (as it is a desert species it is used to getting very dry then occasionally doused by a heavy rain). It loves a bright sunny window sill. You can break of a leaf every now and again to use the soothing gel inside - perfect for sunburn.