Winter is by far my favorite time to be in Montreal, partly for that "arctic look." Hotel rates are much lower (and sometimes there are good "specials" out here) and things in general feel less crowded and frantic.
You know there is that...If you think that Montreal is beautiful head up to Quebec City. As much as I do not like the bone chilling cold it sure is beautiful. Walk down to lower town and look up at the hotel De Frontenac at night. https://c2.staticflickr.com/8/7174/6595055857_3ac8a129fd_b.jpg
Then chose a pub and have a pint. It is like a walk back in time.
It is all really beautiful until you step over a snow bank to cross the street and then step in 6 inches of slush in a pair of dress shoes.