I used to run studded MTB tires, but those things are so heavy and ponderous, the thought of riding 20 miles on 'em is inconceivable, especially when, most of the time, they're not really needed. They're noisy when on the pavement, too.

Switching to 700c wheels with cyclocross tires for the winter was a revelation; I find they handle both slush and powder much better. In part, that's due to their tendency to have low, widely spaced knobs that just don't pack up, but also their narrowness seems to allow them to knife in better.

Yes, they're treacherous on ice, but barely more so than a 26" fat tire. There's an intersection on a secondary road that I go through that always gets compacted snow that glazes over like an ice rink; I've gone down in a fraction of an eyeblink on both wheels, so if your roads are like that, studs are the only way to go. Also, the skinny ones are not as confidence inspiring, but once you learn to trust 'em, you can get along just fine.

Here in Michigan they salt the bejeezus out of the roads, so more than snow and ice, we've got supercold slush, but otherwise dry roads.

Choosing studs or whatever really depends on your local conditions and what kind of surface you ride on.