Hi bernard,
This question probably should live in another part of this board (and I am NOT one of the experts to which straitman alludes), but nevertheless:
Really, your decision. As straitman said, depends on current status, whether you are trying to maintain or increase your status, and what class you want to fly in, and any number of other factors.
Traditionally, buying a Y fare (with real dollars) and upgrading to J (or maybe J to F) has been the best use of points, but is not necessarily the case now, since May 25 changes (upgrades not confirmed till checkin).
Check out Circle Pacific fare rules at oneworld.com. I think your itinerary is doable on that fare, though with a couple of convoluted connections (eg. YVR - YYZ can take 13 hrs via SEA and DFW).
If you have sufficient points to purchase the trip, and are able to snag the award seats then J should be a better value spend than Y (an assumption by me, I haven't done the detailed research), but of course you will be up for taxes.
If you pay for the trip with real dollars then you could possibly avoid some of the taxes by booking through AA, who do not add fuel surcharges onto the price. If you have no current status, you could also consider taking the AA Platinum challenge to fast-track you to AA Platinum status (but only on a paid fare).
There may well be a zillion other (better) options, and I'm sure others will advise what they are.