Get the heated insoles. They are the length of the foot. They look like a set of odor eaters.
http://www.sportsmansguide.com/net/cb/cb.aspx?a=153322
I buy these things up like mad. I won't hunt in the cold weather without these things. In fact, I place these things very high on my list of must-haves for my hunting pack....right up there with my license and ammo! I have one set of rubber boots that I use a vast majority of the time. They are UN-insulated. I wear a pair of wool socks and use these heaters. One word of warning: Don't put them in your boots right away when going to your stand. They heat up pretty good initially. I've actually felt like my feet were burning when walking to my stand. I had to stop and take them back out. Now I just put them in my boots at the point when my feet begin to get cold.
IMO the smaller hand packs and the ones that go under the toes only are nearly worthless for the feet. For one, the hand packs get crumpled up or they work themselves into weird corners of your boots making walking impossible. The toes ones don't provide enough heat for the whole foot. They are better than the hand packs and are better than nothing in a pinch. You really need the full length ones to reap any real benefit.
When the weather turns really nasty, I have a set of pac boots. I don't use these more often because they're bulky and a bit cumbersome to walk in. But these boots combined with the heated insoles have made cold feet a complete non-issue for me on really cold winter days.