Microsoft has announced official prices for the Xbox 360. They plan to have two prices for the system. $299 will buy you a version of the console that does not include a hard drive. For an extra $100 (putting the cost at $399), you can buy the system with a 20Gb hard drive, wireless controller, headset, Ethernet cable, and wireless television-style remote control.
There is still no launch date for the console, so keep checking back.