I had the arcade xbox 360 for about a year. Apart from being louder than my vacuum cleaner and often drowning out game music (especially soft music like Oblivion's), and randomly restarting for no apparent reason, it also had a nasty habit of scratching the game discs, rendering them useless.

It's quite possible that mine was a "monday machine" as we call them here (whatever you produce, you occasionally produce one where everything is malfunctioning), as a few of my friends have 360s and are happy with them - apart from the disc scratching thing, which their consoles seem to do aswell.

So just a tip, check your discs once in a while, and have your drive replaced if necessary. Cheaper than getting new copies of games all the time. I believe you can get cheap generic drives fitted quite easily.