I ride in the dark on my commute one way in the summer and both ways in the winter as it gets dark by the time I am heading home. Blinkers and reflectors are the way to go for the rear but up front you don't want to cheap out too much.
I use a 1W LED up front for commuting in twilight hours but also have a 13W halogen flood for actually lighting the road when it gets dark. The halogen I have will last about 3-4 hours continuous use and the LED on high lasts about 15 hours. The LED lights tend to be pretty focused so you end up with a pretty narrow beam but the halogen has a good spread. With just the LED I don't like to ride at anything over 15 mph if it is really dark but with the halogen over 20 mph is fine.