Bethesda was already announcing New Vegas DLC before the game launched, noting that it would be an Xbox 360 exclusive. Today, that exclusive add-on gets a name, price, and release date.
Come December 21, the "Dead Money" add-on will be available for download off XBL for 800 Microsoft Points ($10). You know what would be even better than exclusive DLC though? A massive patch, preferably the kind that fixes problems without creating new ones. No pressure, guys.