Ideally you'd have two sets of tires, with one for winter, but not many people I know do this with their 4WD Toyotas around here-including myself.
A decent set of all terrains have always worked just fine, and we average around 80 inches of snow per year. In our record snow year of 200 inches back in '07, my neighbor was running practically bald BFG AT's on his beat up old '85 4Runner. And, we live at the top of a hill.
Edit: Yes, stock tires are frequently terrible. My wife's Honda Fit tires were crap and wore out within 15K miles.
A decent set of all terrains have always worked just fine, and we average around 80 inches of snow per year. In our record snow year of 200 inches back in '07, my neighbor was running practically bald BFG AT's on his beat up old '85 4Runner. And, we live at the top of a hill.

Edit: Yes, stock tires are frequently terrible. My wife's Honda Fit tires were crap and wore out within 15K miles.