for what it's worth, Dell have had severe problems with Hitachi/IBM 60 Gb discs in the last while, a friend of mine has had to replace his HDD 3 times in 9 months, I've just done a complete rebuild of a machine here for the same reason. If you're offered a Dell, make sure that it's been retrofitted with a Fujitsu drive, otherwise it could be a problem in the not too distant future.
while it's easy to change the hard drive, getting the data off the old one and transferred to the new one is not so much fun, especially if it's got a FAT32 partition on the front of the drive, which is used to hold the diagnostics.
Be careful out there