I use a balaclava, my girlfriend uses knit headbands (wool?). She knits them herself, they are fairly wide. For my climate a thin balaclava is plenty, the thick ones for motorcycle use are too warm. Headband isn't a bad idea for guys either, (I used to wear one when I had long hair so it doesn't seem odd to me, besides you're all Fred'd out anyway right?) I just haven't found a helmet cover I like and so the balaclava keeps the top of my head warm from the cold air coming through the helmet vents as well as keeping my neck, much of my face and my ears warm. I need to find the time to make my own helmet cover.