Since the 360 has a 60gb hard-drive that means it is probably less than a year old. Since the warranty for the 360 is tied to the console and not the sales receipt that means even if you buy it used your still under warranty. So you will still have around 2 years of warranty on the 360 if anything goes wrong. However make sure he hasn't opened or modded the console in any way because that voids the warranty.
How much is he selling you the 360 for btw?
Also I would wait until after X10 to see if MS announce anything about bundling Natal if that interests you at all.
Overall though the 360 is an amazing console and I highly recommend it. If you do buy the console make another thread with your gaming interests so we can recommend you games.
The definitive evidence that video games turn people into mass murderers
