I discovered this year that we've been running Cooper Wintermaster studless tires for FIVE seasons. Time for new tires. We got studless because we live in town and rarely have to plow through snow. If we lived out in the boonies, like my parents, we'd probably get studded tires. Even still, my father refuses to purchase anything but all-seasons for his '03 Outback and has never gotten stuck even when the roads were pure ice. I'd go studless if you're a city driver and studded if you spent more time out on the backroads. I personally prefer a quieter ride and think the studless are better for what I do during the winter - driving in town on either wet, slushy roads, icy roads, snowpacked roads, or dry roads. I don't have to drive up a mountain through a foot of powder - ever. Plus I never throw a stud on the interstate when visiting relatives across the state.
Some people even claim the studless can match a studded tire if not outperform it. Check out this review to see what I mean. Granted the tires are tested on a '02 Jeep and the review is 4 years old, but the point is made.
http://www.tirerack.com/tires/tests/chartDisplay.jsp?ttid=24
IMHO, get a decent set of studless for around $400 (installed).
Dave