1) full face helmet (of course)
3) neoprene face mask (or baklava if you have one)
4) fleece neck gator
5) Columbia jacket
6) ski gloves (ski gloves are naturally curved to grip your poles, which are similar in size to the handle grips)
7) ski pants
8) wool socks
9) waterproof boots.
Some friends and I went riding on January 3rd one time at the sand dunes. It was so cold we almost couldn't boil water for hot chocolate... but I was toasty warm in the gear listed above. Make sure you have extra gloves and socks though... if something gets wet, you don't want to have to go without.
I usually wear really good quality thermal wear under everything and that really keeps you warm. Also I wear good rain gear over top , it doesn't breath very well and keeps the heat in and the water out. In between some jeans and sweat shirt/tee shirt. All my buddies break my nutz about my half ass riding gear but if it works. I'm thinking of getting myself some "real" riding gear this christmas. :thumbsup: