Well as you guys have said, if it is true, and the next generation XBox doesn't support used games or offline play, then I won't be buying the system. As it is the only exclusive games that raise my interest are Gears of War and Halo, even with those two games and hidden gems thrown in, it is not worth the money, considering once the console is no longer supported, my games and the console are useless.
To be honest, even before this I had serious doubts that I would be investing in the new XBox anyway.