I lived in summit county co for 5 years and drove a bus at a resort. I have no idea how many miles/hours I've logged behind the wheel on snow, but it's probably a fair amount. I drive a 2wd mini cooper and never felt that I needed snow tires, I also drive faster than nearly everyone else out on the road. My advice is do your best to anticipate what other drivers are going to do so that you can plan ahead instead of try to react in time. Also I think someone else referred to the traction circle and it's true, a tire has a limited amount of traction and you can spend it trying to go any direction, but when it's all spent it's gone. So either brake or turn or accelerate, but you're probably not going to do more than one at a time in snow.
Being calm and collected behind the wheel is also important, I usually try and find a way to drive around hazards rather than stop, you have a much higher chance of success.
I think smaller lighter cars are better in snow because they have less inertia so they can stop faster, they're also less likely to roll. I'm also an EMT and I do stop at accidents when I can, I don't have hard statistics but I can't remember a roll over with a car, but I can remember many with SUV's and trucks. The most recent was a pickup with 3 kids in car seats (all ok). I honestly don't know what happens to cause these driver to crash by themselves but it seems like probably they get caught in a little slide and over react causing the crash. My car slides on the highway frequently but with a light car and little corrections it's never put me off the road or into anyone else.
The biggest problems I see on the roads in Colorado are people tend to follow each other too closely, and I for one would appreciate it if people would stay right unless they are in the act of passing a car. I think it's fine if you don't feel like it's safe to do more than 40, but do it in the right lane so you don't get rear ended.