I bought a Bern Brentwood helmet last fall, with the winter lining. The helmet straps keep the lining snug over my ears, so they're always warm. The helmet has open vents (I think there's supposed to be an inside cover I don't have?) but they're too small (and the helmet is too warm) to cause any problems. My face gets chilly sometimes below 20 degrees, but it's infrequent and doesn't cause me enough trouble to buy anything else.

When I bought mine I got the summer version, thinking it would be easy to find a winter insert for cheap. It turned out to be almost impossible to find a shop (online or retail) that carried them, in the end I was lucky to find one without paying $40.