To see better the printing in progress, it is certainly more convenient to add an LED strip on the top of the machine.
sorry for my english not very good, i am french

For this change, you need:

• 30 cm LED ribbon, cool white is better to keep the color but it's more "aggressive" than warm white (it costs less than 4 € 5M cuttable such as http://www.banggood.com/5M-300-LEDs-SMD-3528-Flexible-LED-Strip-Light-Non-Waterproof-DC-12V-p-922277.html)
• A switch (such as http://www.banggood.com/1Pcs-2Pin-Snap-in-On-Off-Rocker-Switch-Control-Black-p-920431.html )
• 50cm black and red wire (speaker wire or your printer installation remains).
• A cover printed in 3D
• 2 screws (VBA 2.5 * 6mm for example)
• Screwdriver, drill, welding iron, welding wire, hands with skills to use tools, pliers
  ...

My Blog in french : http://chezcyril.over-blog.com/2016/01/rampe-lumineuse-pour-imprimante-3d-prusa-i3.html

RepRap

Prusa I3 M-505

Doesn't Matter

0.2 mm

30