I usually like to wear layers underneath a jersey, woolen undershirts etc., rather than wear jackets over the top. When it gets down really cold, I can't go past my Jaggad Reverse Jersey. I've got the pale blue one, but I like the black/white one also. What's good about it is it's thicker than a plain jersey, but not as hot as a jacket.
http://www.jaggad.com/au/product_info.p ... ucts_id=75
with an undershirt Shebeest Thermaflex longsleeve crew
Sugoi Mid-Zero flex tights on the bottom over nix. Plus Sugoi Resistor booties and my Gore Bike Wear WindstopperGloves. That's for my coldest days. Perfectly comfy.