From the Microsoft's press release
"Ending weeks of speculation about which upcoming video game platform will give gamers the most bang for their buck, today at the German Games Convention, Microsoft Corp. revealed that consumers can get their hands on Xbox 360™ — the most powerful and feature-packed next-generation video game and entertainment system — for as little as $299.99 U.S./€299.99/£209.99 starting this holiday season. For gamers who want to experience the ultimate digital entertainment thrill ride, Microsoft also announced a model with hundreds of dollars worth of accessories for $399.99 U.S./€399.99/£279.99, giving consumers the definitive entertainment experience at an unbelievable value right out of the box."

Selling two packages, from Pro-G site

"Xbox 360 Core System - $299 (299 Euros, 209 GBP)
  • Xbox 360 console
  • Wired controller
  • Detachable faceplate
  • Xbox Live Silver membership
  • Standard AV cables

Xbox 360 - $399 (399 Euros, 279 GBP)
  • Xbox 360 console
  • 20GB detachable hard drive
  • Wireless controller
  • Wireless Xbox Live headset
  • High-definition AV cables
  • Ethernet cable
  • Xbox 360 Media Remote Control (limited time)
  • Detachable faceplate
  • Xbox Live Silver membership"

The many peripherals will retail for the following:

  • Faceplate ($19.99, 19.99 Euros, 14.99 GBP)
  • Hard Drive (20 GB) ($99.99, 99.99 Euros, 69.99 GBP)
  • Memory Unit (64 MB) ($39.99, 34.99 Euros, 22.99 GBP)
  • Wireless Networking Adapter ($99.99, 79.99 Euros, 59.99 GBP)
  • Wireless Controller ($49.99, 44.99 Euros, 32.99 GBP)
  • Play and Charge Kit ($19.99, 19.99 Euros, 14.99 GBP)
  • Rechargeable Battery Pack ($11.99, 14.99 Euros, 9.99 GBP)
  • Controller ($39.99, 34.99 Euros, 24.99 GBP)
  • Headset ($19.99, 19.99 Euros, 14.99 GBP)
  • Universal Media Remote ($29.99, 29.99 Euros, 19.99 GBP)
  • Component HD AV Cable ($39.99, 29.99 Euros, 19.99 GBP)
  • S-Video AV Cable (US) ($29.99)
  • SCART AV Cable (Europe) (24.99 Euros, 17.99 GBP)
  • VGA HD AV Cable ($39.99, 29.99 Euros, 19.99 GBP)

Update: Major Nelson has more details on the peripherals with pics.