Conti baron 2.3. It's a little slow in the rear, but otherwise the performance is exemplary in western Oregon winter conditions. Other options are trail kings, high rollers, Hans dampf, purgatory for trail bikes. Try Maxxis beavers for a 29er
I'd second the nomination for the Maxxis Beaver, just got back on the Ardent today for the first time in the past 4 weeks... made me a believer in what I thought I felt with my previous month's rides on the Beaver.
“Beer, if drank in moderation, softens the temper, cheers the spirit and promotes health”