this past winter I used all these things (but not at the same time)

- thin poly beanie, which takes up virtually no room under the helmet
- thin knit hat, which is warmer than the beanie, but takes up more room, but not bad. depending on the temps & exertion level it can get soaked to the point of having to wring it out. that's why I got the thinner beanie
- $6 Carhardt balaclava, surprisingly got a lot of use this winter even tho it does not cover the bridge of my nose
- older, modified (w larger mouth breathing hole) black balaclava with cover over nose bridge
(I like to carry a change, in case one becomes too hot or too wet)
- I wore googles one time this winter. mostly I wore just safety glasses, & actually ditched eye covers for most of the 2nd half of the winter
- in the fall, before it got really cold, I tried a suggestion from another member here to use a hoodie sweatshirt. it wound up being really useful. when I got hot I just pulled the hood back, when I got cold I just put it back up. got a good thin orange model from Walmart. it has no zipper but I wound up liking it anyway
- depending on precipitation I add a cheap clear motel style shower cap to the helmet
- fyi, not a winter commuter anymore, just a joy rider

keep poking around the winter forum & the commuter forum there are a ton of threads on exactly this topic