I advise almost the opposite of vince. with the driving your talking about (same as mine in Ontario) I love my BFG AT's 33x10.5
I had 33x12.5 on 3.5" of lift for a while, with trimming and rims w/3.75"bs I never had any rubbing issues. But I never liked the wide tires from day one, which was a wet snowy day and me on a long drive. This year I went to the 10.5" tires and for road driving I will never go back. On the road they rock, no pull from slush on the side of the road, it cuts through nicely. Offroad they have performed really well too, I haven't gotten stuck (or felt close to) and thats even with breakin path in 2' of powder on an unkept trail. Floatation is great if your always moving, but if you stop your probably going to spin and have to hit bottom anyway. I like these cause if I come to a stop I can backup into broken path, not have to dig down and get stuck because there is packed snow there (that make sense?)
For me, if your doing more road driving than offroad, thinner is better, you don't want floatation on the road, and road manners mean more to me than offroad manners. I much prefer the drive and performance of the 10.5" wide over the 12.5"
edit;
you replied just before me, if you want to keep stock rims, do you have stock lower control arms? or wheel spacers?
I didn't have to trim too much (but am at 4.5" now), but with stock rims you'll want to look at clearancing the inner pinch seam in the wheel well, it may cause a problem when fully stuffed.