Believe It or Not, there's a good bistro at the top of Les Beaux Jeudis (aka "Thursdays").
I tend to go to Montreal over 3-day weekends in the winter for ski season, so many places aren't open (read: Holidays). BUT, Les Beaux Jeudis to the rescue! They were open for dinner on Christmas Eve 2008.
The food was good too! A solid 4.