In reply to spartafan: You should go for one that has an LED and a normal bulb.
Ive got a Black Diamond Gemini, has a really bright xenon bulb that burns the batteries in 3.5 hours, an LED that lasts forever and a spare bulb that lasts 10 hours (or something like that) Been really happy with it, £30 from needlesports.
Tenner cheaper than the equivalent petzl model, though it does have three LEDs to the Geminis one (which Ive found to be more than bright enough for anything Ive needed to do)
Paul