I was skeptical about the need for studded tires, especially here in the mid-atlantic US. However, this year, I have not been able to ride for nearly a month due to ice. We have more ice than snow, especially on the bike trails that do not get treated and on the side streets that I ride on. I've crashed on ice more than I would like to admit, and this year I said no.
Next year I will build up my old Bridgestone MB-2 mountain bike to be my ice bike with studded tires. That way, I can ride in January. It's sometimes nice to have old bikes lying around.