original disc drive
2.16Ghz 160Gb disc circa 2007 in use every day and not one problem or issue whatever you wish to call them. It is ridiculously easy to do a restore from time machine providing you use it & a new 320Gb disc dosnt exactly break the bank these days.
@Renato - Don't forget the case cracks - My sons replaced with no 'issue' even though out of warranty.
@Ian Ferguson - Good for you, I did exactly the same with a failed PC disk, after all why should the oem not honour their own warranty?
@Thermal issues - Wasnt there a study by Google which claimed heat wasnt that much of a contributory factor to failure, I appreciate heat isnt a good thing but not as bad as considered, allegedly. It is located a tad close to the battery, which can get warm when busy, laptop stand?