I deal with motor vehicle fatalities. I swear by snow tires and so do all my accident reconstruction engineers. Best money you will ever spend. Do it.
Yuppers... Snows aren't just for snow! They're softer and have more slits in the tread blocks, so they'll grip on ice and cold pavement better.
You'll get better traction ALL YEAR ROUND if you have a set of summer performance tires for the summer, and winters for the winter.
Since we're on the subject, summer tires are much better than all seasons too. This coming from the guy that put his old MR2 into a concrete wall on the 401 in the rain (doing 110 km/h in the slow lane)...