^^ Yep! Try Poutine at a classic Montreal fast food institution like La Belle Province, or for more variation go to La Banquise on Rachel street.
Montreal is definitely foodie heaven, if you love to eat. I second Pied de Cochon and L'Express (Au P'tit Extra is actually my fave French bistro, it's a little out of the traditional restaurant route, but so lovely!) Look into other spots in the Old Port as well like L'Apartement, Le Local, Grange, Garde Manger (BEST restaurant in Montreal in my opinion, hard to get a reservation!), Holder's and for the best brunch go to Le Carter in the Old Port.
Besides food, shopping and the sights are great here as well. Go to the downtown area for shopping and museums if you like that, definitely walk around the Old Port, and go visit Mount Royal for the beautiful views on the park, the city, and the gorgeous homes that line the Mount Royal area.
Luxury department store shopping is mostly at Ogilvy's and Holt Renfrew, they are on the same street (de la Montagne) 2 street corners from each other! I also second shopping in the Plateau region for cuter versions of boutiques and a "hipster" feel!
So many other things, but let us know what you want to see/do! Montreal is a romantic city IMO so it's a great pick for an anniversary