There are a few options depending on budget.
First, what is your case?
The two prominent options are cold cathodes, and LED strips.
The first being cheaper, and "brighter" but they lack the color quality of LEDs, have ugly cables, and converter boxes.
LED strips are easier to use, flexible, but costly. You get what you pay for though, they look cleaner, better overall color, and certain models are RGB color changeable.