According to Gamespot, Microsoft has recently extended its warranty from a mere 90 days to 1 year for the Xbox 360.  Plus, it’s retroactive, meaning that this warranty covers any Xbox purchased up to a year ago.  Microsoft has changed its warranty length simply to catch up to the standards of Sony and Nintendo, both of whom offer the one-year warranty on their next-gen consoles.  Additionally, Microsoft will extend your warranty another 90 days if you register your Xbox 360.