I'm sure many others can chip in here.
There are often various deals and promos going on with Fairmont. Travelzoo lists quite a number of them often. Also, FPC's own Great Rates thing is a once a month (or so?) promo featuring great discounts at various hotels. They also run quarterly promos, as in now having their summer sale,etc.
I've never booked through 3rd party sites, and I've been VERY pleased with the rates I'm getting at Fairmont. YMMV though
