Lots of good boots out there, I like mucks. I prefer the woodsy elite, comfort rated to -40 and antimicrobial liner so they don't stink.
More important than the boots though is having dry feet. As someone posted earlier, don't leave the house and drive a ways in you're boots. You're feet will sweat and you may not really feel it. As soon as you hit the ice, you'll freeze. If I have any distance to drive I will change my socks when I get there and dry my feet off with baby powder, then put my boots on. Also, make sure your boots are 100% dry. If you typically fish back to back days, get a boot dryer like the sell for ski boots.
Outside of ice fishing, I've sold ski boots for 10+ years and people always complain about cold feet. They always want "warmer" boots, 90% of the time their boots are fine and they can fix their problem by simply keeping their feet dry and making sure they have decent circulation.
Hope that helps.