Hotel Maritime Plaza is a great value hotel in Montreal. Room rates are usually around $100/night. The hotel is large, clean and well maintained. It sits on the southeastern side of the city and is easy to find driving into the city. From the hotel it's easy to pick up public transportation or a cab. The garage is large and pretty easy to navigate (for a Montreal hotel).
One thing I realized when I got to the hotel that surprised me is that the breakfast buffet is only complementary for certain guests - if you booked through the hotel, breakfast is probably included. If you booked through a medium like Hotels.com, they don't include your breakfast.
Also keep in mind that the large hotel and low rates pull in a lot of crowds - last time I was there, there were a couple fraternities and sororities from US Universities holding formal events in the ballroom, and they were ALL OVER the hotel.