Winter bike lights
I hate to say it, but with Winter and dark nights not to far away, I thought I'd recommend the front lights that I have - for both commuting to-from Cambridge, and for my road bike for faster rides.
Others in the group have other lights, but I've gone for Busch and Müller LED lights:
Busch & Müller Ixon IQ front light: this comes with built-in rechargeable batteries and charger, and has two light settings; the batteries easily out-lasted the Dunwich Dynamo ride and are probably good for at least 6 hours use. 58 Euro from http://www.starbike.com/php/product_info.php?lang=en&pid=9965
On my commuting bike I have a dynamo and have another B & M light; Busch & Müller Lumotec IQ Cyo N plus, 53 Euro: http://www.starbike.com/php/product_info.php?lang=en&pid=11493
Both lights are fantastic - if anything, too bright when cycling close behind another cyclist, but you can really see the road when there are no streetlights.
David
Cateye
I've got a Cateye HL-EL320 and TL-LD610 Light Set - paid about £50. Very good for the money, especially as now only £36 in the Wiggle sale:
http://www.wiggle.co.uk/cateye-hl-el320-and-tl-ld610-light-set/