Mercedes' 4-Matic is often overshadowed by Audi's and Subaru's, but it's an awesome system and combined with ESP it really works, especially for people that get a little nervous in the snow. Our E300 had ESP and my wife loved it, but I always switched off as it seemed to intervene too early for my liking.
The best winter vehicle we've ever owned, and by some margin, is the Forester. It's nearly 500lbs lighter than our Legacu Outback was, meaning shorter stops on poor traction surfaces. The shorter overhangs really contribute to offroad capability, and meant I had no problem clearing a pretty significant snow-berm a few weeks ago in the mountains. If it had an ESP-type of system, it would be pretty much perfect, but it's really, really, really good without it.