The best deal was zellers at $399 with extra DS3, and LBP. While that deal is done, I wouldn't be surprised if they don't something like that again in December for the holidays.
I also expect a a $100 price drop in late jan to feb. Just a gut feeling. 360 is much cheaper now, and those are traditionally slow months. If it was me, I would drop it before christamas, even if there is a small loss involved and get the install base up. They would recoup the loss in increased game sales over the next couple months.
~S