If I get an Xbox, what are the chances of it breaking?

Being a teenager, I don’t have any constant cash income, so I don’t want my hard-worked-for money to be wasted. I would really like to purchase the new xbox 360 (friend has one and I love it), but I hear that it has a roughly 1 in 10 chance of breaking soon within the time of purchase. Is this statistic correct, have any of you had a broken xbox, and do you think that it is worth it to buy an additional 1-year warranty (on top of the free 90-day one) for $30.00?