I've had mixed results using CFL bulbs in a traditional drop light. Some aren't all that low temp and their toughness varies greatly. Better off just going LED like the others have said, just be sure to get a light with surface mount LED's like the Saber. The older style LED's with the dome shaped lense don't have the same focused light output and it's gets too dispersed if the light itself is more than 2 feet from what you're working on. At least that's how it is with my father's Craftsman led light. The battery is good and it's great for lighting up under the dash, but hang it on the hood and it doesn't do much good at all, needs to be held closer to what you're working on. Below is the one my father has.
http://m.sears.com/craftsman-cordles...160903102847:s