hopperja

No, no, no. The most important thing is a great tail light. Buy the absolute best tail light you can afford. In my opinion, a DiNotte 140L is the minimum if you're going to be riding regularly for any period of time in the dark. Remember, if you're going to be riding regularly in the dark, you'll be investing in your safety for the long term. Spend more than you want on a good tail light and it'll serve you well. Take out a loan if you have to.

I have commuted hundreds of times/thousands of miles in the dark. I have found the headlight is of secondary concern. You'll probably be riding with traffic, so the headlight isn't as important. On-coming traffic will be at least a lane away, and often the street lights and car lights will light your way.

1- get a good tail light, the absolute best you can buy.
2- get a reflective vest. I've found the $5 Harbor Freight one to be better than the $40 Amphipod vest.
3- put lots of reflectors on your bike: I have 4 spoke mounted reflectors on each wheel, a rear reflector, and ton's of DOT reflective tape (also called conspicuity tape) on virtually any flat surface.
4- get a decent headlight. If you can't afford one after spending all your money on a great tail light, a $20 Maglite LED will do until you can afford better. I've commuted in the dark with one. While it wasn't anything like a good headlight, it was enough to see by when the street lights were distant.

My favorite headlight is the Baja Designs Strykr, though I like my DiNotte 200L, Fenix L2DQ5, and Magicshine as well. I have found one drawback to very bright headlights, however. Unfortunately, the critters (rabbits and opossums, mainly) are attracted to the light. There's nothing more annoying that cruising down the MUP at 18 MPH in the dark and having a rabbit run to the side of the trail, turn back, and then at the last minute dart out in front of you. I've had rabbits do that, as well as opossums, and one skunk. Fortunately, I didn't hit the skunk. So far, I've only run over one opossum and one rabbit. On a side note, I was surprised at how much softer a rabbit is than an opossum.