I fish in some very cold Colorado winters. I have both kinds of waders, but find I stay warmer in the breathables.
What the others said about no cotton and layering underneath. Silk, synthetics and wool work OK.
I also layer the top with similar materials. At most a synthetic long john top or turtleneck, a wool sweater, a fleece jacket and a breathable windbreaker outerjacket.
And a warm hat and possible ear band.
The layering helps both in staying warm and by allowing you to take stuff off so you don't get too hot. Frozen perspiration is no fun.
Fingerlees wool gloves are my usual choice. I don't like the neoprene gloves. I've heard that wearing latex "medical" gloves under the wool actually helps, but have never tried it.