Originally I was going to cover the ceiling drywall (which is a good fire barrier) with reed fencing for a rustic look. But after the insulation netting (which holds the insulation in place between the rafters) was installed its white color reflected so much light into the room, opening up the shadows, that I decided to leave the drywall uncovered and white. I went with blown cellulose insulation because it has a high R value, was reasonably priced, and the fact that it's made from recycled newspapers meant it was a good environmental choice.