My winter helmet is a Bell Tourlite knockoff w/taped vents. I tried wearing a balaclava under it once (at ~10F), found it to be too hot.
I have ridden at -8 with it, 180's (earmuffs, that go behind the head), and a face mask like the one posted above by skijor. That is what I wear ~0F.
10 degrees Fahrenheit and above, I swap out the face mask for a neck gaitor.
Tomorrow night, they are predicting -15F, I will probably try the balaclava again.
As always, YMMV