First off there is a Couch. Most people here seem to use that exactly the same as sofa. When discussing these items, settee is also an appropriate term, although not as commonly used in Vancouver.
Now one other word that is frequently used is Chesterfield. In Canada, this seems to be used interchangeably with sofa as well, although it usually refers to a big, over-stuffed sofa like the one below. In England, this refers to a specific type of couch and is more a name brand.