The Climbers Shop have a great deal on Petzl Tikka 2 Plus headtorches. they normally sell for £40 and we've now got them for just £25.
They have a powerful 50 lumen output, giving a 35m beam - easily enough for a evening descent off the crag or an overnight bivvy. It offers an amazing battery life of 140h too(on the lower setting). They also make a great Christmas stocking filler for friends and family.