1UP - during my senior design class, I worked with those super bright leds, from superbrightleds.com... they don't NEED a resistor - but they sure are safer with them. I had a few burn out when we plugged them directly into the power supply. After that, we added 100 Ohm resistors into our specs. It didn't affect the brightness much, and it did stop us from wasting the bayonet bulbs.