If you don't have a ton of money to spend I recommend the Planet Bike Blaze 2 watt headlight - $54 - $59. *(I've owned the Blackburn 3.3 too, it's bright. If you have no occasional street lights on your ride, you may want a rechargable system.) I used to ride with two Blackburn 3.3's strapped to my old bikes handlebars. It worked well. I was able to point one on flash a head of me towards any traffic and one down at the road to illuminate potholes and other obstacles. Boy did cars slow waaaay down when the one was on flash. They often stopped and said they thought I was a moped.
That's some visibility.
"Things look different from the seat of a bike carrying a sleeping bag with a cold beer tucked inside." ~Jim Malusa
2009 Trek 520-Brooks B-17 Special in Antique Brown
2010 Surly Long Haul Trucker-Brooks B-17 Standard in Black
1983 Fuji Espree Single Speed-Brooks B17 British Racing Green