I've never been really tolerant of cold temps so I go to great lengths to stay warm. While some folks say it doesn't get cold enough down here in the South, just ask ol Iron Bull what he thinks about WY 20 degrees vs. Southern 20 degrees. Must be something with the humidity.
Anyway, Under Armor boxers, Under Armor Metal Gear top, Under Armor cold gear bottoms for a base layer. Ulfrotte 600gm wool zip up top mid layer (and Ulfrotte 400gm wool bottoms if it's really cold). Cabela's down vest, Day One Camo insulated pullover. Day one Camo fleece bottoms, poly liner sock, wool blend socks, LaCross 1200gm insulated rubber boots. Under Armor face mask, Under Armor beanie. A few of the hot hands heat packs thrown here and there. There are some mornings I would love to have on more, but this is about the most I can put on and still shoot.
Unless I'm hunting on my own property, I typically have a 1/2 hour to 45 minute walk so I leave the truck in just the underwear and maybe wool mid layer...freeze the first 10 minutes until my body heats up from the exercise. The key for me is NOT sweating too much before layering in the stand. I can use much less if I'm relatively dry when I finally get up there. Although I thought it was a gimmick at first, under armor has definately made me more comfortable because of it's ability to move sweat away from your body and keep your base layer dry.
Looking forward to trying out some of the Sitka gear in the future. I have high hopes it will further increase my comfort.