According to someone I know who works at the Media Markt, a 10% failure rating for electronic devices is normal. Which is why guarantee should never be limited to anything less than a year (a guarantee is basically a limitation on the responsibility of the manufacturer making a working product, it's not a service like most people think).
However, the Xbox 360 goes over the 10% mark. According to Gamespot, 54.2% of all those consoles fail within one year.
For PS3, the rating is 10.6% (usually overheating problems), and for the Wii 6.8% (usually dust in disc drive).
Read more...