So-called "all-season" tires have been on the market for decades. Coupled with front-wheel-drive and anti-skid systems, they have allowed many folks to avoid mounting a true snow tire for the winter months.
But there are two trends in tires you should be aware of:
1) Styling priorities have led to manufacturers fitting wider, low-profile tires on a variety of cars. Wide and low profile, on balance, makes a tire worse in the snow. Pressures to improve tire fuel economy have also worked against the snow utility of all-seasons.
2) Winter tires have improved their behavior from the era of knobby, loud "snows" that looked like they belonged on an army truck. New tread patterns and rubber compounds make them quieter on dry roads, yet even more effective on frozen stuff.
If you choose to go with winter tires, note that vendors such as The Tire Rack and Discount Tire Direct offer packages with the tires already mounted on a new set of wheels. Switching the entire wheel/tire combo for the winter is more cost-effective than having two sets of tires mounted on your existing wheels twice a year.
Whatever you choose for tires, make sure there's enough tread on them as you head into winter. Getting through snow requires the deepest grooves possible, and worn tires on which you might have skated by in summer will put you into the ditch in the white stuff. See if you have enough with this coin-based test from The Tire Rack