I keep seeing these expensive light bulbs that are guaranteed to last for 5-10 years. Some also require less wattage than respective traditional light bulbs. For example, GE has this spiral light bulb that lasts as long as 8 conventional bulbs and only requires 17-27 watts. Are these type of light bulbs worth buying for the sake of saving money on electric bills? Do they produce a nice incadescent glow even though they are flourescent?