Official Press Release:
LinkinPrime Edit
Circuit City confirms price drop on all 3 versions:
Elite - $449.99
Premium - $349.99
Core - $279.99
http://www.xbox360fanboy.com/2007/07/31/circuit-city-ad-confirms-360-price-drop-on-all-models/
Wal Mart ad
CheapyD Edit: It appears this image originated from Sith Ninja at Modojo
Not "huge" but $50 is $50.
Thanks to Ugamer X for the picture:
Toys R Us Ad

via ugamer and zoo
Full Press Release: http://www.xbox.com/en-US/community/news/2007/0806-consoleprice.htm...Family of Consoles
Xbox 360 will enhance the value of its entire family of consoles beginning on August 8. At a new price of $349.99, Xbox 360 offers an unsurpassed experience right out of the box with a 20 GB hard drive, Wireless Controller, Xbox 360 Headset, and more.
If you're looking for the ultimate value and the freedom to customize your console as you see fit, Xbox 360 Core System now has an estimated retail price of $279.99. Xbox 360 Core System provides everything you need to hit the ground running, while giving you the ability to expand with new features and accessories you want.
Dressed in black and equipped with a 120GB hard drive, Xbox 360 Elite will be priced at $449.99 if you want the premium games and entertainment experience.
In anticipation of this year's largest blockbuster game launch, the Xbox 360 Halo 3 Special Edition Console will hit store shelves in September with a price of $399.99. Featuring an authentic Spartan green-and-gold finish, this console includes a matching Xbox 360 Wireless Controller, 20GB hard drive, Xbox 360 Headset, 360 Play & Charge Kit, and more.
LinkinPrime Edit
Circuit City confirms price drop on all 3 versions:

Elite - $449.99
Premium - $349.99
Core - $279.99
http://www.xbox360fanboy.com/2007/07/31/circuit-city-ad-confirms-360-price-drop-on-all-models/
Wal Mart ad

CheapyD Edit: It appears this image originated from Sith Ninja at Modojo
Not "huge" but $50 is $50.
Thanks to Ugamer X for the picture:
Toys R Us Ad

via ugamer and zoo