Dave Forde at Profectio has done a lot of work to come up with a list of of Canadian company blogs divided into categories such as legal firms, marketing service firms, PR agencies (Hill & Knowlton and Thornley Fallis), advertising agencies, media (of varying types), technology firms, and post-secondary schools. I'm sure he'll get some more suggestions for additions and categories. I know I plan to take a thorough review to see which feeds I can add.