I think a big thing people are missing is the type of snow you drive in. Here in CO our snow is pretty dry so it's pretty easy to drive through it. Like Punk said, all seasons do just fine here. They got me through our "Storm of the Century" here in March (6-7 feet in two days)
I'm not too experienced with the cement that falls outside the Rocky Mountain area, but I would imagine it's quite a bit different in the slushy junk the rest of you get. I'm not sure it would warrant dedicated snows though.