OK. I understand that "bagels" is not a restaurant. But, if you go to Montreal, you must eat fresh bagels. Seriously, if you have not had baked-that-morning-fresh bagels you have not lived.
There are several fresh bagel shops in Montreal. Two of my favorite are:
St. Viateur -- located at 263 St-Viateur O., they are open 24/7
Fairmont -- located at 74 Avenue Fairmount O