Thanks for all the quick responses on Montreal hotels (I still haven't decided). A couple more questions...

Any recommendations on restaurants (perhaps ones with a romantic atmosphere)?

What are the not-to-be-missed attractions?

Does it make sense to get a rental car? A car might be nice to have to drive around and get a feel for the city (out of the cold) but I suspect parking is difficult and a car won't be of much use just getting around downtown. Is it better to just take a cab to the hotel and then walk/ride the metro?