I've owned several AWD cars - A6 quattro, X3, Land Rover LR3 and now X5. Each of them at some point went thru a severe snow ordeal. Like others said, tires play the biggest role, followed by ground clearance. I got stuck in A6 simply because the snow was too deep for it. LR3 went thru incredibly deep snow obstacles but got stuck after I parked for some time on a small incline - the tires were almost bald and coudn't get any grip on ice beneath the snow. At the same time, my wife made a successful trip in X5 from VA to NY and back in one day during the 2010 storm when the roads were shut down - on almost new OEM Bridgestone runflats.

So IMHO any AWD car will do fine in snow, as long as you consider what tires you have and how deep into snow you go.