Not sure how, but I just snagged it for $45.87. I had stuck it in my cart earlier, it had jumped to 53 so I forgot about and then just a few minutes ago it was the low price but with a timer on the checkout page... Hidden gold box or something?
Yeah, that doesn't include the $9 coupon. Checked out price for me was $41.99 and since it does have a price guarantee, there is always the chance that it'll go lower before release. Probably not likely; but, possible.
They did have the CE for pre-order back in August; but, reached the limit they are receiving from Blizzard. Worked out well for me since I had $60 in credit. :)