Buying a "montreal SEO" domain is something I've been meaning to do for a while now, and it has good justifications for my SEO.
First, owning montrealseo.ca gives me more legitimacy as far as being an SEO consultant goes. Second, it's good for my own SEO. Obviously, I'm targeting "Montreal SEO," and I intend to be number one for that term soon enough (2-3 months). When people link just using my URL, I'll have the keywords in the link text. Also, though this is controversial, some SEOs consider that having keywords in your domain helps. Can't hurt at any rate. Third, it's good for branding. The words are real dictionary words, and the address is easy to remember. The domain market uses these points as standard criteria for judging the quality of a domain.