+1 on the layering. Even for the hands-- I use military-issue wool. In the morning I have three layers on each hand: two thin and one very thick knitted layer as the outermost. I'm finding that on my ride home, I can get by with just the two thinner layers on the hands, here in Boston/late February.

My bike has a basket with bungee net on the front. When I need to adjust layering, the article of clothing goes-into/comes-out-of the basket, and I usually don't have to stop.