Seagate Momentus Thin ST500LT012 Internal Hard Drive 500GB (6.5 cm (2.5 inches), 5400RPM, 16MB cache, SATA II) (Personal Computers)
Had the hard disk built into my Dell, after the older hard drive had suffered irreversible damage and did not want to. Installation is very simple, it is very quiet, fast and thin. 500GB are an OK size for the replacement Laptop, therefore from me 5