The curly ones! I have tried all brands but they are the newer bulbs. Seems the first ones were made to last much longer. I have two older bulbs that are still burning from several years ago. The new ones light up faster then the older ones and are brighter but are made not to be turned off and on. I write the date on the bulb every time I change it. We put in new light fixtures and new breaker box in our house redo so I know our electrical system is not defective.