Given where you live, it depends on whether or not you plan to run seperate summer and winter tires. If you are going to has just one set of tires I would suggest the narrower tires. A wider tire will give you some flotation (not dig down as easy a narrow tire) help off road, but that same flotation can be a negative on snowy roads. A narrow tire will be better at digging down to the hard pack on snowy roads.
Is the truck your daily driver or more of a weekend play toy? If its more of a play toy the MT would probably be fine. If it is your daily driver you might be better off with the AT for all season use unless there is a place near you that can sipe the MT for you.
I agree on the AT being better for a DD. The MT's are gonna be hands down better in mud and their ability to clean themselves out. But they are gonna be noisier on the road and wear faster. As much as I would like MT's I don't want to be replacing them as much as I drive on the highway. For me the BFG AT's are the best compromise. They work good enough in the mud as long as I know their limits for clogging up.