Home lighting is usually classified into four distinct types, each serving its specific purpose: task, accent, informational and ambient lighting.
Task lighting, as the name suggests, is light used to help you with a task such as office lamps, light for a desk or light for playing music; this type of lighting is usually directional and it’s adjustable depending on your needs. Companies such as Quattro or Ott-Lite make these types of lamps, from adjustable task-lights to small spot-lights.
Accent lighting is usually used for decorative purposes, such as bringing out an aquarium for instance or a piece of art in your home (i.e. a painting, a vase). You can do without accent lighting however, as task lighting can be directed and hence serve a similar purpose.
Informational lighting is basically so you can see where you are without bumping into things: your closet light, the light in your hallway, to upstairs or garden-pathway lighting are all good examples of informational lighting.
Lastly, ambient lighting is the light that will surround the main room; whilst it will likely be diffused with other lighting types and not be too distracting it should always be there to help you see around the room you are in.