I am currently looking to upgrade my computers hard drive but i am unsure of which one to get. I currently have three choices but i am willing to look around at other hard drives. The two choices are 1). Western Digital Caviar Blue 500GB SATAII 16MB Cache link: http://www.amazon.co.uk/Western-Digital-Ca...5500&sr=8-6 2). Generic Hard Disk Drive 500GB SATA II Max Cache 16mb link: http://www.amazon.co.uk/Generic-Hard-Disk-...5500&sr=8-8 3). Seagate OEM 500GB Barracuda 7200.12 Internal Hard Disk Drive (7200RPM, SATA, 32MB Cache) link: http://www.amazon.co.uk/Seagate-OEM-Barrac...5500&sr=8-9 I am not sure which of the following drives are better and which make is better. This may sound dumb but i am also unsure of what "Cache" is, so please help. As you would have seen all the drives are 500gb and under 50 pounds. Please Help!