The Top 5 Sofa Styles:

Sleeper: Sleeper sofas are popular because they are dual-purpose. During the day they are used as seating, but at night the cushions can be removed to reveal a foldout bed. Sleeper sofas are an ideal choice for those without a designated guest room. They are simple to set up, and they provide comfortable sleeping. Sleeper sofas are heavier than traditional sofas, but their benefits outweigh the extra weight. Sleeper sofas are traditionally upholstered in cloth.
Loveseat: Usually part of a set, the loveseat sofa is one of the most popular types of living room furniture. Loveseat sofas are fashionable because they offer added seating but don't take up as much room as a traditional sofa. Loveseats are designed for a maximum of two people and can be made from either cloth or leather.
Traditional: The traditional three-seat sofa is still the most popular. Nearly every home has some form of this sofa in the living room. These sofas come in a wide range of colors and fabrics, including microfiber and leather. Depending on the manufacturer and style, the design of the sofa will vary. Some have high backs, and some have removable cushions, while others do not.
Chaise: Chaise sofas are a modern twist on the sectional sofa. Unlike sectional couches that have a separate cushion for each space, chaise sofas have one long cushion that sits at an angle from the rest of the couch. Chaise couches allow for users to lie comfortably without the edge of the cushions poking them.
Find this original buying guide, Top 5 Sofa Styles at Overstock.com.