My tires say "all-season" on them. Doesn't that mean anything?
Sure, but it's not really going to do much when the snow starts to fly. These days, most new cars are fitted with all-season radials -- tires that are designed to do most things well but few things superbly. By sacrificing a bit of warm-weather performance, they gain a small amount of cold-weather talent. Think of it as the difference between a band-aid and a tourniquet -- the band-aid can help if things aren't too serious, but it's not going to save your life. The best all-seasons can limp you through a mild winter, but they pale in comparison to purpose-built snow-and-ice rubber.
Want some perspective? According to The Tire Rack, one of America's largest tire and wheel outlets and a respected tire tester, winter tires can provide up to twenty-one percent more traction than all-season tires in similar conditions. That's nothing to sneeze at.
Hey! I've got a four-wheel drive truck! I spent last winter hauling yokels out of ditches with my F-950, brute strength, and bare American hands! I don't need this junk!
As my smart-aleck Jewish grandmother used to say, "sure you don't." Four driven wheels can help you accelerate in slippery conditions, and most all-wheel-drive systems can instill a surprising amount of confidence in the average driver. What they can't do is defy the laws of physics. All-wheel drive rarely provides a useful cornering or braking advantage for the average person. In addition, because most four-wheel-drive vehicles weigh more than their two-wheel-drive brethren, they ask more of their tires when it comes to turning or stopping. Your F-950's weight and ground clearance may have kept you from harm's way and let you play good samaritan, but imagine where you could go with a little extra traction. (Monster truck with snows on it? May we suggest the North Pole?)
Hey! I've got electronic stability control! I spent last winter driving around on rubber balder than a crazy Britney Spears and I never went off the road once! I don't need this junk!
First off, Crazy Britney was pretty dang bald, so you either got really lucky or you barely left the house. Second, while electronic stability programs (ESP) are wonderful, lifesaving devices, they can't work the impossible. Like four-wheel drive, ESP is entirely dependent on your tires -- it merely maximizes the traction of the rubber you have. It can't magically add extra grip.