About 4 years ago it was cold every day. The warmest day I hunted that year was 6, the coldest morning was -30 and breezy. I can honestly say I don't think I enjoyed hunting a single day of that season. Rather it was more of an obligation. That was a few years after I moved to MN and before I really understood what cold weather hunting was. I've since started trying to spend some money here and there on better cold weather stuff. This spring I finally broke down and bought an IWOM XT.
http://www.iwomouterwear.com/content/iwom-xt-1
Basically an improved version of the heater body suit, and they guarantee you won't get cold your first year or your money back. I'm pretty excited about it and hope it's as good as they say.