Peace Lily's are well known for their purifying abilities. They filter more indoor pollutants than most other plants, so are great for bedrooms or other frequented rooms. Inside the tropical plant's pores, toxic gases like carbon monoxide and formaldehyde are broken down and neutralized.
Avoid direct sunlight, but do give them lots of bright filtered light. Soil should be kept moist, but not soggy. A wilted plant can easily be revived with a big drink of water.