Xbox 360's hardware is very unreliable, I checked it out with a guy in my neibourhood a few weeks back(cause I was supposed to purchase it for the GTA4 release), turns out his console RroD in about 6months, then he asked for a replacement, which he received after a month after days of explaining over the phone. Heres the best part the replacement which arrived RroD a week later and microsoft are not ready to replace it for 3-4 months because they are out of stock or some crap like that. So now I've dumped he idea of getting a console decide to get some stuff for my PC instead.
Best of luck kerby hope you don't have to wait too long.