I have one simple rule for driving in snow and ice:
It's not the v, it's the delta v.
For the physics impaired, this is basically what heropsychodreamer above said. You can go fast in the snow, as long as the road is straight, flat, there are no cars around you, and there's no wind. If you have to change the velocity of the car at all, that is the part that you need to do carefully and slowly.
In my opinion, the hardest part of driving in winter is dealing with all the other cars around you. If you're going a different speed than all the other cars around you, you will be forced to change your velocity, which is when you can get in trouble. You need a huge following distance in these cases, and also you don't want people tailgating you. If they are, then I guess you need to fix that (yes, sometimes, you may need to speed up in the snow to be safe.)
Other considerations are visibility and heat. If your car doesn't have a rear window defogger, it should. They're the law in most states anyway. You will need to run the defrosters as well, and in some cars, you need to have the air conditioning on as well to extract moisture from the interior to prevent the windows from fogging up. You want the car warm, but not too warm that you become drowsy. Also, use a good washer fluid that doesn't freeze easily--you'll need it to clean salt off the windshield to see properly.
And one more thing--brush all the snow off of your car before you start moving. Including the roof. There's nothing more annoying than being behind someone who has chunks of snow flying off their vehicle and crashing into your car. In New Jersey, it's illegal as well. Get a good snow brush, and use it. If you can't reach the top of your SUV, then you shouldn't be driving it in the snow anyway.