In reply to Father Faff:
I own a 4 led Lucida LED headtorch which has a bulky lens unit (300 hours on batteries) and a smaller 4 led Black Diamond for night climbing (150 hours)
The Petzl Tika? is neat but slightly less bright so I did not go for that.
I tried one make with mulitcontrols (2 led. 6 led, SOS, redbacklight)and a possible max of 6 leds but it kept resetting itself if batteries rattled, thus plunging me into darkness. It was also not conspicuously brighter.
I only replace the batteries once a year, and use these headtorches for backup while exploring mines. If I'm not out in 3 weeks then battery life is the least of my worries.
I will never use conventional bulbed head torches ever again, and suspect that my big car/cave spotlights will soon be available in led style.