For my top half I use a base-layer top which I got from Mountain Warehouse to go skiing. Over this is a shirt and sweatshirt, then an "Anti Freeze" mid-layer jacket, followed by my regular textile bike jacket.
For the bottom half it's Heat Holder socks, base-layer pants, jeans and textile pants, plus my boots.
I have a set of Gerbing Heated Gloves which I will never stop singing the praises of, because they warm down the back of the hands and fingers, rather than heating the palms which lets your fingertips and backs of the hands get cold.
I also have a windproof balaclava for under my helmet if it's really cold