The latest rumor is that the console will be called the "Xbox Gold".
This rumor has arisen from a rash of domain registrations by Microsoft, claiming such sites as XboxGold.biz, XboxGold.com.co, XboxGold.us, XboxGold.at, XboxGold.ch, XboxGold.jp, XboxGold.mx, XboxGold.ru, XboxGold.tw and XboxGold.fr.
Of course, Gold has been associated with Microsoft's online subscription service, but having a name like "the Xbox Gold" does set up a nice naming string - the next Xbox would be the Xbox Platinum, then perhaps the Plutonium.
It would also set up a fantastic color scheme for the next-gen box; imagine a metallic gold color scheme. Wait, let Mega Modz Planet.