LED's may be frowned upon but there is a new form called a Luxeon LED. Do not be deceived- a 5w luxeon is a powerful light and I can vouch for that. LED's- even the luxeon ones use the battery far more efficiently and do not drain batteries quite so much.

http://www.use1.com/exposure/

This is the home page and battery life is fantastic if used sensibly. I did a night ride last year and only did the 40 miler- About an hour after I finished the fast 80 milers came in and those lights were still bright after 8 hours use. And I do mean bright.

Although I am looking at lights for next winter, and it will probably be one of the Exposure lights- I have found a helmet lamp invaluable. Toss up between the 3w luxeon as a helmet lamp or the 2x5w as the main riding light- but Finances still tight for this year.

Yet another one to look at is the Blackburn. sorry -no home page but uses 2x3w luxeons.