I have to say that as an East ender i may be able to add a little something here. There are LOTS of great eateries out East of Papineau or dare i say St-Laurent street.
On Masson street a cute place called Potion Magique, ElZazium on Laurier(i think) is a great laid back place, Roberto's on Belanger near Sagard is nice...Le petit Gavroche, french cuisine, nothing pretentious on Jean-Talon and Delorimier.
Those are all places you will find just walking around. Montreal is a great town for such excursions, i was born and raised here(since moved to NYC) and i have done it many times...So many restaurants in this town its hard to be left with no options!