Insulation, usually Thinsulite and the like, can help keep your feet warm. The extreme case is the ice fisherman's "moon boots." However, if you properly fit footgear so you can wear thick wool socks, and you stay active on the trail, you may not need insulated footgear unless you slog through snow or slush.
Ice fishermen, for example, can stand or plywood, or, like boaters, pull garbage sacks over their lower body when they sit to fish. Insulated inserts that pad and support the foot also improve foot comfort on cold ground.
The problem with insulated footgear is simple. Most insulated boots are too hot much of the year. One solution to this is the traditional pa that features a gun rubber bottom, leather top and a removable felt insert. Two pairs of thick wool socks insure a good fit without the felts in milder weather. Do, if you wear felt insulation frequently, buy two sets so one can dry while you wear the other.
L.L. Bean Guide Shoes and Sorrel's are classics in this field. Both types of footgear are ideal where you face puddles, slush and mud. They come in a variety of heights. I favor ankle to calf-heights for most outdoor needs.
The "chain-type" sole patterns on these do not seem to bog down in mud like most Vibrums. I favor uppers with metal quick lace systems even though the metal "ears" eventually break off and need replacement. Rubber bottoms do wear out faster than leather.
L.L. Bean has offered replacement bottoms and reconditions uppers for several generations. I have a pair of their guide shoes that have had three bottom replacements and my survive several more.
Tip: If you fish in damp areas, try a pair of guide shoes.
RUBBER BOOTS, WADERS and HIPPERS
Knee high rubber boots are favored by commercial fishermen and, in combination with a good set of foul weather gear, they keep boaters dry and, in case one goes overboard, they kick off quickly. Rubber boots also suit rural types that slog around in the mud. But the two types are exclusive.
Mud boots need more sole pattern than boater's boots designed to stick on slick decks. For mud, I favor "Green Wallies," the green British standard knee-high boot now available from most mail order houses and many shops. The English know how to deal with mud, and their boots feature an ankle strap that offers more support and, in combination with the top fastener, a better fit than loose boots. They seem to last longer too.