knobbies suck for cornering on the wet. suck. i think that the idea is that knobbies work better in gravel and dirt, where the the crap on the ground has some friction at least against itself. for snow and ice this isn't the case. I think that they conditions that would make knobbies work better (packed snow, perhaps) are rare and tend to (at least in the case of packed snow) be slipperly as hell with or without knobbies anyway.

I mean this is at least how I arrived at my conclusion last year to roll my 23s through the winter. There were maybe two days where conditions were too slick for my setup and I'm unconvinced that knobbies would have made it better while they definitely would have been inferior to 23s in the 'normal' conditions of winter -- wet pavement and some slush.

I rode to work every single day last winter except when it rained and my 23s were fine. Ask me about how Look pedals get screwed up in the snow and ice sometime, though.