Track lighting is one of the most common lighting sources you will find in museums and galleries. It is the least obtrusive, and it produces the most general environmental ambiance of a lit space. Although it does provide a general spread of light, it emphasizes the art, but subtly. Track lighting is usually hung from the ceiling and there are usually a few bulbs on one track. Some people will use track lighting along with another type, such as spot-lighting, to provide that extra emphasis on the artwork without creating an extremely dramatic effect.
Accent lighting, or spot lighting, is useful for giving a piece of work a very dramatic effect. Sometimes it's used above the artwork, and sometimes it's used below. Accent lighting is a good choice for three-dimensional works, in settings where it is possible to use this type of light. If you use accent lighting without any other lighting around, the artwork with be very in-focus and can create a tunnel-like, private viewing experience for the viewer who is close to the work. But from far away, the lighting looks very dramatic, and for some the dramatic lighting will deter them from approaching the work. If you want your lighting to be subtle, don't use accent lighting alone. Use a combination of accent lighting with another type in order to spread the light around.
Recessed lighting is usually in the ceiling. Recessed lighting is probably the easiest and most clean looking type of lighting to use in a home, or even a gallery space. Because the lights are recessed into the ceiling, the cords and hardware are all hidden, and this gives the entire space a clean look, allowing for viewers to focus more on the artwork. Recessed lighting can be used in tandem with spot lighting and/or track lighting, depending on the effect you want to create. Some recessed lights have adjustable fixtures so that they can be pointed in different directions. These are better than the stationary ones, and begin to function more like track lights when you point them toward the artwork.