With fenders, you can fit 700x32 in front (maybe 35, but that would be really tight), and 700x40 or 42 behind. For soft-terrain or snow rides, I think it's a good combination since one usually have more weight on the rear wheel. However, if you want to fit studded tires, you'll have a problem, because you will be lacking 1-2 mm of clearance on the front wheel.

A few other bikes have better clearance.

– Cannondale T-xxx: I heard quite often that you fit 700x37 with fenders and some room to spare on both front and rear wheels. Ditto for Surley LHT.

– Bruce Gordon BLT: Fits 700x42 or 45 with fenders, so you'll have lots of room for studded tires and mud, slow, sleet... Besides, you'll have gears that are actually fit for touring.