This time of year I am ski touring so I exert a lot of energy and produce a lot of heat. Last week it was in the single digits in the Colorado High Country and this is what I used: 
On my skin up the mountain I wore a base of Smartwool light boxers, Smartwool 150 Light 3/4 long underwear, Darn Tough padded mid weight ski socks,  Under Armour Heat Gear T-Shirt under a Smartwool 250 1/2 zip mock Turtle. For mid outer layer on the way up I wore my Marmot Scree Pants, Arcteryx Delta AR Zip FLeece, Arcteryx LEAF Cold WX Contact Glove, Ball cap and Oakley Sunglasses. Once at the top I took off the Arcteryx Fleece to dry and vented moisture off of my top base layer and torso until I got a chill at which time I put on my Marmot Calene puffy and my Marmot Full Zip Mantra pant shell over my Scree pants. I donned my Arcteryx Rush Jacket and began my descent. About half way down I began to generate heat again so I doffed my Puffy and put on my now dry Arcteryx Delta AR Fleece. 
In temps above 20 degrees I will forgo the Scree pants and only wear my Arcteryx Beta AR pants over my Smartwool base. I typically also carry an extra Smartwool 1/2 zip top, Arcteryx Toque, Hestra Falt Gloves for adaptability.  
This system allows me to vent and control core body temp through a variety of options and layers during high and low activity.