I live in the northern lower penninsula of Michigan. We get plenty of cold.
I wear the LaCrosse "Burly" knee high, insulated, rubber boots. For all but the coldest days, these work great for me. I use a boot dryer to keep the moisture out (a MUST DO). When the temps fall to near zero, I simply put one of those disposable handwarmers in the toe of each boot, and my feet are actually too warm. These boots are less bulky than most other cold weather boots.
I used to wear pac boots, but I have found using the little handwarmers a great alternative.
People always ask me..."aren`t your feet cold?"
Nope...toasty.