My commute in is completely in the dark, on rural roads with no lighting whatsoever except for about 1 mile through a town. It's a 10.5 mile trip.

I have a home-built 20W halogen MR16 spot in the front, and an amber strobe in the back. Cateye 3-LED light on the helmet and a Nashbar cheapo 5-LED red blinker in the back, for backup.

I don't think I'd want to go much less on the lighting; as it is I cut my speed at times because I'm afraid I'm riding too fast for my light grasp. I'm keeping it down to about 17 MPH max, on roads that, in the day, I hit 25 on regularly.

I have a 2.3AH SLA battery on the rack to power it, but it's barely making the 40 minute commute. I'm really overstressing the battery. However, due to some pointers from the "total geekiness" thread here, I found batteryspace.com and a 4AH NiMH pack for $31; I'm getting one right away.