Work hard on your LSAT score, period. Get into the best school that you can. The post suggesting that you can just go to a lesser regional school, say Windsor, and simply finish top of your class is correct but I advise you to be weary of putting yourself in a position where you need to be in the top 20% to have a chance at the job you want. When comparing schools assume you will be right at the 50th percentile and then ask yourself from there which one is more likely to contribute to your success.
The problem with the aforementioned poster's comment is that the concept of "regional schools", while useful when considering American law school applications, isn't applied well to success in the Canadian legal job market. As I said earlier, there are just 15 common law schools in Canada, and to graduate from any of them will tend to allow you to work in any "region" throughout Canada.
The majority of legal jobs in Canada reside in the Toronto or the GTA. Biglaw firms in Canada take law school rankings less to heart than say, the American law school rankings, but they can and will matter at the top (generally corporate) firms - especially when you're competing with GTA graduates.
Also consider that many Canadian law schools "specialize" in a particular field of law, and you should consider your stats and your goals when making a choice of law school applications. For example, UofT is particularly well known for it's training in the fields of private/corporate law; Osgoode in administrative and Constitutional law; and uOttawa in international law. Moreover, each of these schools differ in their emphasis on numerical and non-numerical admissions factors. In other words, your LSAT and GPA should reflect your goals, and vice versa.
Anyway, to the OP: the LSAT matters, and you should take the test with the intention of doing your best. Don't settle for a 155. But you won't need a 170 either. Take the test, weigh your options, and choose the school that is best suited to your long term career goals.