winter commuting necessities? (help me shop!)

[newfsmith]

A waterproof but breathable jacket, preferably with pit zips. I wore one of these for 6 of the 8 years I commuted.
http://www.bicycleclothing.com/Water...n-Jackets.html
Too warm for summer use, but an excellent fall, winter, spring jacket. It was roomy enough to put several layers underneath. I wore it down to -5F/-20C, all for a reasonable price. Their rain pants are too warm for anything but the slushing days, but they are great for that.

For chilly fall rains I used wool socks with water proof socks on top & SPD sandals, the sandals would be dry by the time I headed home. For winter riding I gave up my SPD pedals and used MTB platforms with mini toe baskets. I found that an ordinary pair of womens winter boots worked very well in the cold, giving good chill proofing of the ankles.

I carried a winter emergency pannier: a space blanket, toe warmer and hand warmer (Grabber Mycoal), an extra fleece, 2 pairs of dry wool socks, a spare pair of gloves, and my leather chopper mitts with heavy wool mitten liners. I went a little overboard because my commute was through a rural area. I also carried "Yak Trax" in my jacket pocket so that I could walk better on icy surfaces. The worst fall I took in 6 winters of riding was standing in the work parking lot after dismounting.

As for lighting, I was continually evolving. I believe in LED lights. My home-brew system had a car horn, 1W LED head light, and a 56 LED truck taillight. It was very noticeable, but even with lots of lights, drivers aren't expecting cyclists in the winter, so you have to be extra alert.

I would suggest you put your money in your lighting system. You probably have enough layers around the house to keep you warm. They don't have to be cycling specific if they are going to be covered with a jacket. Thrift store wool sweaters are fine.