I use a MTB with GEAX Blades for winter. They are an agressive widely spaced knobby pattern which works well for the snow because it doesn't load up. It can still get pretty floaty on ice, but nothing short of studs will help you on ice. For all kinds of snow the GEAX Blades tire works great.

The other thing about winter riding is that slush and salt are murder on a bike. It's much better to have a dedicated winter bike so you don't trash a good bike. An old MTB is the perfect choice since they are inexpensive, and lots of cheap knobbies are available. My winter bike has been through 2 winters so far in this capacity, and I'm about to get it ready for a third.