Living rooms are used for many different purposes and having the appropriate living room lighting is very important. Some rooms used purely for entertainment, others for watching television and many for a whole host of other activities. It's important to have appropriate living room lighting that not only looks great in the space, but also accommodates all of the events that take place there.
Table lamps are important for providing task lighting. It's a good idea to have a few scattered throughout the room. For a formal look place a pair of matching lamps at either end of a console table or on end tables. If you don't like things to be quite so symmetrical it's perfectly fine to split up a pair and use them in different spots in the room, and if you prefer a less pulled together look use lamps that don't match.
Floor lamps are great for adding light where there's no table surface (they're often used in corners). They don't take up very much space and are great for distributing light in awkward spaces.
Wall sconces are great for adding a little ambient light to the living room. They look lovely when placed on either side of a mirror or piece of art and act as terrific decorative accents. That said, when it comes to providing light they likely won't be enough. You'll want to use other sources of light as well.
Chandeliers and pendent lamps can be a fun decorative touch in living rooms. They provide a nice overall glow to the space and draw the eye upward. What's great about them is that they tend to be unexpected in living rooms and can add some real depth. Just make sure that your ceilings are high enough (about 9') so that no one hits their head.
Living Room Lighting Tips
Ideally you want to use different types of lighting to provide a nice mix. While pot lights and track lighting can be practical and provide a lot of overhead light, they're not really the best choice for living room lighting. Ultimately you want a mix of task and ambient light so try mixing floor lamps, table lamps, and maybe an overhead light and/or sconces. Make sure there's enough light near reading or work areas and also use light to call attention to unexpected or special places.
One of the best things you can do is to add a dimmer switch to every single light in the room (do this with every light in the house if you can). The ability to soften or brighten the light allows you to totally change the mood in the room. They're not very expensive and it makes a huge difference.