I just wanted to post a follow-up about the Louis Garneau balaclava. I took it on a 3-day bike tour. Temps between 32 and 60. It ROCKS! It is very thin (so no problem getting the helmet over it; and when I take it off I can tuck it away very small). Stretchy, so I could easily pull it down under my chin (if warmer) or back up over my mouth (if colder). It did not feel constricting or look funny.

Someone asked me about the neck gaitor. I LOVE wool neck gaitors and wear mine everywhere when I walk or run. However, now I definitely prefer the balaclava for biking. I used to wear the neck gaitor biking, and when my chin got especially cold (usually on a descent) I was trying to hold the dang thing up with my teeth. The balaclava requires no holding up. And it can't slip off your ears either.

For colder temps (under 35 or so) I'd probably wear both together for biking - the balaclava, with a neck gaitor over it.