For the record, I'm a 150lb rider with plenty of winter experience and a decent bike handler. I ride 700x23 road tires even when there are still a few patches of ice left on the ground without undue worry, so my tolerance for tire slippage is high. Here are some of my tire impressions:

Continental Top Contact Winter, 26x1.9 - these are excellent tires for city riding in winter if you don't have enough ice to need studded tires, they have a lot of grip on pavement that is cold and wet or covered up to 4" of snow, perform acceptably well on roughly packed ice as the tire volume helps dampen the bumps, and they are just narrow enough to cut through slush. Rolling resistance is quite low for tires of this width. The one place these tires do not perform well is over loose dirt or gravel trails covered in snow or ice, the texture that gives them added grip on cold and wet does absolutely nothing on loose soil, you might as well be on thin road slicks. Cannot comment on service life, yet, but my experience so far says that the rubber is fairly resilient and much tougher than conti's road tires, which tend to square off rather quickly.

Michelin Country Rock, 26x1.75 - a fair tire for winter riding, very inexpensive and hard wearing, work acceptably well on packed ice, snow up to 6" deep, and over both pavement and dirt. However, when the pavement is dry these have noticeably high rolling resistance, and in temperatures below zero the sidewalls become very stiff.

Schwalbe Delta Cruiser, 700x35 - These tires perform surprisingly well in winter conditions, particularly over dirt and gravel covered in snow. On pavement these are suitable in a few inches of snow and are acceptable on small patches of ice. These do tend to slide more than other tires on piles of slush or packed snow.

Kenda Small Block 8's, 700x35 - These are great gravel tires and work well if you're going to ride trails on a snowy day as long as the temperatures are low enough that mud isn't much of an issue. On pavement these cope with snow and slush well enough since they're narrow enough to sink through it and the tread provides more traction in such conditions than a slick would. However, traction suffers on icy pavement with these these tires, and they are definitely not suitable for muddy conditions especially if the local dirt is very fine, since mud packs into the tread and you can end up carrying around several pounds of soil on your wheels.